Write each in ax^b form where n can be either positive or negative integer

Write Each In Ax^b Form Where N Can Be Either Positive Or Negative Integer

Answers

Answer 1

Answer:

a.  [tex]$ x^{-5} $[/tex]

b.  [tex]$ 3x^{-2} $[/tex]

c.   [tex]$ \frac{4}{3}x^4 $[/tex]

Step-by-step explanation:

We have to know the two results to compute the problems.

1.  [tex]$ x^a . x^b = x^{a + b} $[/tex]

2.  [tex]$ \frac{x^c}{x^d} = x^c . x^{-d} = x^{c - d} $[/tex]

a. [tex]$ \frac{x^3}{x^8} $[/tex]

Using (2), we get: [tex]$ \frac{x^3}{x^8} = x^{3 - 8}[/tex]

[tex]$ \textbf{= x}^{\textbf{5}} $[/tex]

b. [tex]$ \frac{6x}{2x^3} $[/tex]

[tex]$ = 3\frac{x}{x^3} $[/tex]

[tex]\textbf{= 3x}^{\textbf{-2}} $[/tex]

c. [tex]$ \frac{28x^6}{21x^2} $[/tex]

[tex]$ = \frac{4}{3}x^{6 - 2} $[/tex]

[tex]$ = \frac{\textbf{4}}{\textbf{3}}\textbf{x}^{\textbf{4}} $[/tex]

Hence, the answer.


Related Questions

Write an equivalent expression for 20(x-5)

Answers

Answer:

40(x-10)

Step-by-step explanation:

Mrs. Rivera ate 3/8 of a
pizza and Ms. Carter ate 4/8
of a pizza. How much pizza
did they eat altogether?

Answers

Answer:

They ate 7/8 of a pizza altogether.

Step-by-step explanation:

So, you know Mrs. Rivera ate 3/8 of a pizza and Ms. Carter ate 4/8 of a pizza.

You add 3/8 + 4/8 and you get 7/8.

The ate 7/8 of a pizza altogether.

The quantity of pizza  that Mrs. Rivera and Ms. Carter ate altogether is equal to [tex]\frac{7}{8}[/tex]

Given the following data:

Fraction Rivera ate = [tex]\frac{3}{8}[/tex]Fraction Carter ate = [tex]\frac{4}{8}[/tex]

To calculate how much (quantity) pizza  they ate altogether:

A fraction can be defined as a numerical quantity that isn't a whole number.

Hence, a fraction is simply a part of a whole number.

In this exercise, we would add up the two fractions, so as to calculate how much (quantity) pizza  they ate altogether.

[tex]Total \;quantity = \frac{3}{8} + \frac{4}{8}[/tex]

Lowest common multiple (LCM) = 8

[tex]Total\;quantity = \frac{4\;+\;3}{8} \\\\Total\;quantity = \frac{7}{8}[/tex]

Read more: https://brainly.com/question/6201432

What is 4,095 divisible by

Answers

Answer:

5

Step-by-step explanation:

the answer would be 819

Answer: 5

Step-by-step explanation:

What is the value of t in the following equation? t + 14 = 2 712

Answers

Answer: t = 2698

Step-by-step explanation: Subtract 14 from 2712 to get the value of t

How many times greater is the 5 in
458,039 than the 5 in 271,145?
A. 10
B. 100
C. 1,000
D. 10,000

Answers

Answer:

D.

Step-by-step explanation:

Final answer:

The 5 in 458,039 is 100 times greater than the 5 in 271,145 because it represents 50,000 while the 5 in 271,145 represents 500. This can be determined by understanding place values, as each digit's value depends on its position in the number.

Explanation:

The 5 in 458,039 is in the ten thousands place, meaning it represents 50,000. The 5 in 271,145 is in the hundreds place, meaning it represents 500. To understand how many times greater one is than the other, we would divide 50,000 by 500. The result is 100, therefore, the 5 in 458,039 is 100 times greater than the 5 in 271,145. So, the answer is B. 100.

This problem involves place values in numbers, where each digit in a number has a different value depending on its position.

Learn more about Place Values here:

https://brainly.com/question/35447631

#SPJ11

How can this 12×2+2³ make 120

Answers

Step-by-step explanation:

[tex]12\times(2+2^3)\qquad\text{use PEMDAS}\\\\\text{first power}\\\\=12\times(2+8)\\\\\text{next addition in parentheses}\\\\=12\times10=120[/tex]

An object is launched from a platform.
Its height (in meters), x seconds after the launch, is modeled by:
h(x)=-5x2verb +20x+60
What is the height of the object at the time of launch?

Answers

Answer:

60 feet

Step-by-step explanation:

The height, h (in meters), of the object launched from a platform is represented by the equation

[tex]h=h(x)=-5x^2+20x+60[/tex]

where x is the time (in seconds) passed after the launch.

The time of launch is [tex]x=0[/tex] (0 seconds passed after the launch)

Substitute [tex]x=0[/tex] to find the height:

[tex]h=h(0)=-5\cdot 0^2+20\cdot 0+60=60\ feet[/tex]

Sgt. Merritt has bought a house now that his tour of duty is up. He wants to stain the wood floors of the living room, which measure 18x14. The stain costs $120 per square yard. How much will it cost to stain floor of the entire room?

Answers

It costs $ 30240 to stain floor of the entire room

Solution:

Given that,

Sgt. Merritt has bought a house now that his tour of duty is up

He wants to stain the wood floors of the living room, which measure 18 x 14

Therefore,

length = 18 yards

Width = 14 yards

Find the area:

[tex]Area = length \times width\\\\Area = 18 \times 14\\\\Area = 252[/tex]

Thus area of wood floors is 252 square yards

How much will it cost to stain floor of the entire room?

The stain costs $120 per square yard

[tex]Cost = 252 \times 120\\\\Cost = 30240[/tex]

Thus it costs $ 30240 to stain floor of the entire room

To stain Sgt. Merritt's living room floors, which measure 18x14 feet, first calculate the area in square feet, convert to square yards, and then multiply by the cost per square yard. The total cost will be $3,360.

To determine the cost to stain the wood floors in the living room, first we need to calculate the total area in square yards since the stain is sold by square yard. The room measures 18 feet by 14 feet.

Step 1: Calculate Square Footage

Multiply the length and width in feet to get the square footage:

18 feet × 14 feet = 252 square feet

Step 2: Convert Square Feet to Square Yards

There are 9 square feet in 1 square yard. Therefore, we divide the total square footage by 9 to convert to square yards:

252 square feet / 9 square feet per square yard = 28 square yards

Step 3: Calculate the Cost

The cost to stain one square yard is $120. So, we multiply the total square yards by $120 to get the total cost:

28 square yards × $120 per square yard = $3,360

Therefore, the cost to stain the entire living room floor will be $3,360.

To make a ribbon and bow for a hat, Stacey needs 5/6 yard of black ribbon and 2/3 yard of red ribbon. How much total ribbon does she need

Answers

5/6 yards is 30 inches 2/3 yard is 24 inches so 54 inches

Eric worked for 13 hours each day For 6 days hen the next day he worked 5 hours How many hours did Eric work in complete Answer ASAP

Answers

Answer:

83 Hours

Step-by-step explanation:

First do 13x6=78

then add 5 hours to 78 hours and you get 83

Which of the following is equal to one million three hundred thousand?
A 1.3×106
B 1.3×109
C 1.03×106
D 1.03×109

Answers

1 million is 1*10^6

300 thousand is 3*10^5

Since 300,000 is one power of ten below 1 million, it's either A or B.

The correct choice is A, however, because of 1 million being 10^6. We choose the biggest value we get.

Hope this helped!

Kyle is purchasing a refurbished phone. He is looking at the phone models 4, 5, and 6, with a protective case in red (R), blue (B), or camo (C). What are all of the different choices he has? A) {4, 5, 6} B) {4R, 5B, 6C} C) {4R, 4B, 4C, 5R, 5B, 5C} D) {4R, 4B, 4C, 5R, 5B, 5C, 6R, 6B, 6C}

Answers

Answer:

The choices Kyle has are option D.)  {4R, 4B, 4C, 5R, 5B, 5C, 6R, 6B, 6C}

Step-by-step explanation:

The choices available to Kyle either of the models 4, or 5 or 6 and each model can have a protective case which can be either red(R) or blue(B) or camo(C).

So Kyle can have model 4 in red protective case, 4R, or model 4 in blue protective case(4B), or model 4 in camo protective case (4C) or

Kyle can have model 5 in red protective case, 5R, or model 5 in blue protective case(5B), or model 5 in camo protective case (5C) or

Kyle can have model 6 in red protective case, 6R, or model 6 in blue protective case(6B), or model 6 in camo protective case (6C).

So the choices Kyle has are option D.)  {4R, 4B, 4C, 5R, 5B, 5C, 6R, 6B, 6C}

Answer:

D

Step-by-step explanation:

A survey of all beings on planet Pib found 20% preferred umpt juice to all other juices. if 6 brings preferred umpt juice, how many beings were surveyed altogether?

Answers

Answer:

30 people.

Step-by-step explanation:

In a survey it is found that 20% of the people preferred umpt juice to all other juices.

Now, if 6 of the surveyed people are being preferred umpt juice, then we have to find the total number of people that were surveyed altogether.

So, 20% of the people being surveyed is equal to 6 people.

Therefore, 100% of the people is equal to [tex]6 \times \frac{100}{20} = 30[/tex] people. (Answer)

7 + (5 – 9)2 + 3(16 ÷ 8).

Answers

Answer:

5

Step-by-step explanation:

7 + (5 - 9)2 +3(16/8)

7 + (-4)2 +3(2)

7+(-8) +6

7 -8 +6

7 -2

5

Combine like terms to create an equivalent expression 2/5m - 4/5 - 3/5m

Answers

Answer:

-1/5m-4/5

Step-by-step explanation:

2/5m-4/5-3/5m

2/5m-3/5m-4/5

-1/5m-4/5

34. If each interior angle has a measure of 175.2°, how many sides does the polygon have?

Answers

Answer:

75 sides when the interior angle is 175.2

Step-by-step explanation:

these problems are all done the same way. Subtract the interior angle from 180 and divide the result into 360

360/(180 - 175.2)

360 / 4.8

75 sides

A runner increased her distance from 9 miles to 12.5 miles a week. Find the percent increase in mileage.

A. 28%

B. 39%

C. 58%

D. 42%

Answers

Answer:

39 percent is increase in mileage.

Thus, the correct option is B. 39%.

Step-by-step explanation:

Given:

A runner increased her distance from 9 miles to 12.5 miles a week.

Now, to find percent increase in mileage.

Previous mileage = 9 miles.

Present mileage = 12.5 miles.

Mileage increase = 12.5 - 9 = 3.5 miles.

Now, to get the percent increase in mileage:

[tex]\frac{Mileage\ increased}{previous\ mileage} \times 100[/tex]

[tex]=\frac{3.5}{9} \times 100[/tex]

[tex]=\frac{350}{9}[/tex]

[tex]=38.88\%.[/tex]

Approximately the percent increase = 39%.

Therefore, 39% is increase in mileage.

Thus, the correct option is B. 39%.

Please help I’ll give 50 points

The question is down below with the fractions please answer as fast as you can

Answers

Answer:

C

Step-by-step explanation:

(4√6)/(5√6)

= 6^(¼) ÷ 6^(1/5)

= 6^(1/4 - 1/5)

= 6^[(5-4)/20]

= 6^(1/20

When dividing roots, multiply them together: 4 x 5 = 20

Invert the product: 1/20

Raise the number under the root by that

Answer = 6 ^ 1/20

For each set of three measures determine if they can be angle measures of a triangle

Answers

The options that  can be angle measures of a triangle is

2. Set: 25°, 130°, 25°

How to find measure of triangle

To determine whether a set of three angle measures can be the angle measures of a triangle, you can use the sum of internal angles of a triangle which is 180 degrees

Let's analyze each set of three angle measures:

1. Set: 41°, 112°, 52°

41 + 112 + 52 = 205

This cannot be a triangle

2. Set: 25°, 130°, 25°

25 + 130 + 25 = 180

This can be a triangle

3. Set: 30°, 40°, 90°

30 + 40 + 90 = 160

This cannot be a triangle

4. Set: 132°, 141°, 31°

132 + 141 + 31 = 304

This cannot be a triangle

Write a ratio as a ratio of whole numbers in lowest terms
$1.00 to $1.50

Answers

Answer:

Step-by-step explanation:

50

The ratio of the whole numbers in its lowest term is ratio $2 to $3 i.e.  [tex]\mathbf{\dfrac{2}{3}}[/tex]

A ratio of two integers a and b can be represented into a fraction as numerators and denominators.

[tex]\mathbf{\dfrac{a \to numerator}{b \to denominator}}[/tex]

To recognize and determine the ratio of the whole numbers in their lowest terms, we will multiply both the numerator and the denominator by 10.

i.e.

[tex]\mathbf{=\dfrac{1.00}{1.50}}[/tex]

[tex]\mathbf{=\dfrac{1.00\times 10}{1.50 \times 10}}[/tex]

[tex]\mathbf{=\dfrac{10}{15}}[/tex]

DIvide both the numerator and denominator by 5;

[tex]\mathbf{=\dfrac{2}{3}}[/tex]

Therefore, we can conclude that the ratio of the whole numbers in its lowest term is ratio $2 to $3 i.e.  [tex]\mathbf{\dfrac{2}{3}}[/tex]

Learn more about ratio here:

https://brainly.com/question/18956877?referrer=searchResults

a jar of peanut butter contains 452 with a standard deviation of 10.4 g assuming a normal distribution find the probability that a jar contains less than 449 grams

Answers

Answer:

0.3859

Step-by-step explanation:

Assuming on the average, a jar of peanut butter contains 452 grams, with a standard deviation of 10.4 grams.

Then we have

[tex] \mu = 452 \: and \: \sigma = 10.4[/tex]

We want to find the probability that a jar contains less than 449 grams.

We first determine the z-score of x=449 grams using:

[tex]z = \frac{x - \mu}{ \sigma} [/tex]

We plug in these values to get:

[tex]z = \frac{449 - 452}{10.4} [/tex]

[tex]z = \frac{ - 3}{10.4} = - 0.29[/tex]

Now we read from the standard normal distribution table the area that corresponds to a z-score of -0.29

P(X<449)=0.3859

Final answer:

To find the probability that a jar contains less than 449 grams, calculate the z-score and use a standard normal distribution table or calculator.

Explanation:

To find the probability that a jar contains less than 449 grams, we can use the standard normal distribution and the z-score formula. The z-score is calculated as (X - mean) / standard deviation. In this case, X = 449, mean = 452, and standard deviation = 10.4. By substituting these values into the formula, we can find the z-score, and then use a standard normal distribution table or calculator to find the probability.

1. Calculate the z-score: (449 - 452) / 10.4 = -0.2885

2. Use a standard normal distribution table or calculator to find the probability associated with a z-score of -0.2885. The probability is approximately 0.3830, or 38.30%.

Learn more about Probability here:

https://brainly.com/question/32117953

#SPJ11

Please show work for both problems

Answers

Answer:

3)  x = 15; 95 and 85      4)  x = 12; 98 for both angles

Step-by-step explanation:

2x + 65 + 3x + 40 = 180       Set the equations equal to 180

5x + 105 = 180                      Combine like terms

     - 105  - 105                      Subtract 105 from both sides

5x = 75                                  Divide both sides by 5

x = 15

Plug 15 into both equations

2(15) + 65 = 95

3(15) + 40 = 85

4)  5x + 38 = 9x - 10             Set the equations equal to each other

  - 5x          - 5x                    Subtract 5x from both sides

 38 = 4x - 10

+ 10       + 10                         Add 10 to both sides

48 = 4x                                  Divide both sides by 4

12 = x

Plug 12 into both equations

5(12) + 38 = 98

9(12) - 10 = 98

Friday, a store sold 10 blue shirts and 20 white shirts. what percentage of the shirts sold were blue? give answer to the ones place

Answers

Answer:

10+20=30

10 is what percent of 30?

10 is 1/3 of 30

Step-by-step explanation:

10 is 33.33% of 30

so 33% of the shirts sold were blue

33.33% of the shirts sold were blue.

Given that, Friday, a store sold 10 blue shirts and 20 white shirts.

We need to find out what percentage of the shirts sold were blue.

What is the percentage?

The percentage is defined as a given part or amount in every hundred. It is a fraction with 100 as the denominator and is represented by the symbol "%".

Now, 10+20=30

We need to calculate 10 is what per cent of 30.

Let the percentage be x.

So, x% of 30=10

⇒x/100 × 30=10

⇒3x/10=10

⇒3x=100

⇒x=33.33%

Therefore, 33.33% of the shirts sold were blue.

To learn more about the percentage visit:

https://brainly.com/question/15308590.

#SPJ2

Plz, I'm desperate for 5 answers. help me ASAP on the attachments I'll give everything I can, Brainly award, high ratings, thanks, everything, I need help! Please I need help!

Answers

Answer:

[tex]1.\ 8n+4\\\\2.\ 5x+13\\\\3.\ x+3\\\\4.\ x-6\\\\5.\ 4x+1[/tex]

Step-by-step explanation:

1.

[tex]Sum=2n+6+6n-2\\\\Sum=2n+6n+6-2\ \ \ \ \ \ \ \ (using\ commutative\ property\ of\ addition\ a+b=b+a)\\\\Sum=8n+4[/tex]

2.

[tex]Sum=3x+9+2x+4\\\\Sum=3x+2x+9+4\ \ \ \ \ \ \ \ (using\ commutative\ property\ of\ addition\ a+b=b+a)\\\\Sum=5x+13[/tex]

3.

[tex]Difference=(3x+5)-(2x+2)\\\\Difference=3x+5-2x-2\ \ \ \ \ \ \ [using\ distributive\ property\ -(a+b)=-a-b]\\\\Difference=3x-2x+5-2\ \ \ [commutative\ property]\\\\Difference=x+3[/tex]

4.

[tex]Difference=(4x+3)-(3x+9)\\\\Difference=4x+3-3x-9\ \ \ \ \ \ \ [using\ distributive\ property\ -(a+b)=-a-b]\\\\Difference=4x-3x+3-9\ \ \ [commutative\ property]\\\\Difference=x-6[/tex]

5.

[tex]Difference=(6x+2)-(2x+1)\\\\Difference=6x+2-2x-1\ \ \ \ \ \ \ [using\ distributive\ property\ -(a+b)=-a-b]\\\\Difference=6x-2x+2-1\ \ \ [commutative\ property]\\\\Difference=4x+1[/tex]

Is -8-2(3+2n) + 7n equivalent to -30-13n? Explain why or why not.

Answers

It is not equivalent because when you distribute it, it will be -14+3n

15 POINTS PLEASE HELP PPLESSE

Answers

Step-by-step explanation:

Hope it helps you in your learning process.

Use the remainder to divide 5x^2+9x-2 by x+3. What is the remainder?

Answers

Answer:

16

Step-by-step explanation:

Using the Remainder theorem

f(x) divided by (x + h) then the remainder is the value of f(- h)

here the divisor is (x + 3), thus remainder is f(- 3)

remainder = 5(- 3)² + 9(- 3) - 2 = 5(9) - 27 - 2 = 45 - 29 = 16

Read this scene from The Miracle Worker Act 2.


(ANNIE insists, and HELEN gets rid of ANNIE’S hand by jabbing it with the needle. ANNIE gasps and moves to grip HELEN’S wrist; but KATE intervenes with a proffered sweet, and HELEN drops the card, crams the sweet into her mouth, and scrambles up to search her mother’s hands for more.)


How do these stage directions add meaning to the play?


The stage directions explain the characters’ facial expressions.

The stage directions illustrate the appearance of the room.

The stage directions describe how characters react to Helen.

The stage directions reveal Annie’s manner of speaking.

Answers

Answer:

The stage directions describe how characters react to Helen.

Step-by-step explanation:

In the given scene, the different characteristics of Helen as well as how other characters react when they see Helen is depicted in the scene. Other characters in the scene react differently to Helen when they come in contact with her. This is the main objective of the stage direction. It shows the interaction between Helen and others.

The stage directions represent the additions of the meaning to the play in terms of the stage directions describe how characters react to Helen.

The following information should be considered:

In the given situation, there is various characters of Helen and how the other character react at the time of seeing when Helen represent in the scene. The other characters scene react in a different way at the time of contacting. It represents the main aim of the stage directon. Also, it shows the interaction that lies between Helen and others.

Learn more: brainly.com/question/17429689

A bag contains 6 gray tiles and 3 blue tiles. Jenny reached into the bag and picked a tile
randomly, and then without replacing it, picked a second tile.

What is the probability that she
picked a gray tile with her second pick given that she picked a blue tile with her first pick?​

Answers

Answer:

The probability that Jenny picked a gray tile with her second pick given that she picked a blue tile with her first pick = 0.25

Step-by-step explanation:

i.) there are 6 gray tiles and 3 blue tiles

ii) the probability that Jenny picked a blue tile first is given by

[tex]\frac{number\hspace{0.1cm} of \hspace{0.1cm} blue\hspace{0.1cm} tiles }{total \hspace{0.1cm}number\hspace{0.1cm} of \hspace{0.1cm}tiles\hspace{0.1cm} } = \frac{3}{9} = \frac{1}{3}[/tex]

iii) the probability that Jenny picked a gray tile with her second pick without replacing the first tile[tex]\frac{number\hspace{0.1cm} of \hspace{0.1cm} blue\hspace{0.1cm} tiles }{total \hspace{0.1cm}number\hspace{0.1cm} of \hspace{0.1cm}tiles\hspace{0.1cm} } \times \frac{number\hspace{0.1cm} of \hspace{0.1cm} gray\hspace{0.1cm} tiles }{total \hspace{0.1cm}number\hspace{0.1cm } of \hspace{0.1cm}tiles\hspace{0.1cm} - 1 } = \frac{3}{9} \times \frac{6}{8} = \frac{1}{3} \times \frac{3}{4} = \frac{1}{4} = 0.25[/tex]

The probability that Jenny picked a gray tile with her second pick given that she picked a blue tile with her first pick = 0.25

URGENT!!

These triangles are similar looking at the angles.

True or false

Answers

Answer:

False

Step-by-step explanation:

Answer:

False

Step-by-step explanation:

Other Questions
in terms of S, N, and A, what is the value of B in the equation S=n/2(a+b) Psychologist Robert A. Rescorla's contribution to the study of classical conditioning involved his insight that for learning to occur, the _____ stimulus must be a reliable signal that predicts the presentations of the _____ stimulus. Which kind of rhetoric is Anthony most clearly using in the passage?OA. PathosO B. LogosO C. RepetitionO D. Ethos Some leading-edge companies are applying the prosumer concept. Here, firms team up with their suppliers and alliance partners to satisfy their customer needs. a. Trueb. False Apples are a normal good. The government increases income taxes on households, and increases business taxes on apple farmers. We would predict that the price of apples will __________ and the quantity of apples exchanged will ________. which best tell the main idea of the third paragraph of the e-mail? letter from birmingham jail Part A: What tone does Dr. King use in his argument? Assertive Passive Admiring Angry brainly You bought 1,000 shares of Tund Corp. stock for $68.12 per share and sold it for $90.03 per share after a few years. How will your gain or loss be treated when you file your taxes? As a capital gain taxed at the long-term tax rate As a capital gain taxed at the current ordinary-income tax rate Nelson has been blind since birth. However, an fMRI of his brain shows intense activity in his visual cortex when he is reading Braille. How can this activity be explained? Maya spent 40% of her savings to pay for a bicycle that costs 85$. How much money was in her savings to begin with ? which of the following is not an example of genetic variability 1. A population of snails has phenotypes that range from tan to dark brown.2. An asexually reproducing single celled organism produces 10 offspring in its lifetime.3. Allele #1 for wing size in a butterfly has the following sequence of bases: GGAT, while Allele #2 has this sequence: GGAC.>4. A population of squirrel has multiple alleles that code for fur coloration How did religion affect the lives of the Puritans? James found a strong relationship between stress and depression in his correlational study. However, he suspects that another variable was responsible for the results. This is an example of the ________ problem.a. fourth variableb. fifth variable c. third variabled. first variable According to Socialists, what parts of the economy should the government control? Geographical similarities between U.S. and Canada According to "Dance, Modernity, and Culture," what are three differences between ballet and Martha Graham's technique and dancers. Corn lacks the essential amino acids isoleucine and lysine. Beans lack the essential amino acids tryptophan and methionine. Soy contains all the essential amino acids. Use this information to complete the following statement: Many traditional diets combine corn (e.g., tortillas) with beans to provide ________.a. all the essential fatsb. all the essential amino acidsc. all the essential fats and additional micronutrientsd. multivitaminse. additional micronutrients 15. The volume of a rectangular pyramidis 10,500 cubic centimeters. It has alength of 15 centimeters and a width of85 centimeters. What is its height? The people of Mesopotamia were protected by the Describe two disadvantages to human health of an exclusively plant-based diet?