SAT Math : How to multiply exponents

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #21 : How To Multiply Exponents

If  and  are positive integers and , what is the value of ?

Possible Answers:

Correct answer:

Explanation:

The question tells us that 22a ( 22b )= 16.

We can rewrite 16 as 24, giving us 22a ( 22b )= 24.

When terms with the same base are multipled, their exponents can be added:

2(2a +2b) = 24

Since the base is the same on both sides of the equation, we can equate the exponents:

2a +2b = 4

2(a + b) = 4

a + b = 2

Example Question #1 : How To Multiply Exponents

(b * b* b7)1/2/(b3 * bx) = b5  

If b is not negative then x = ?

Possible Answers:

–2

–1

1

7

Correct answer:

–2

Explanation:

Simplifying the equation gives b6/(b3+x) = b5.  

In order to satisfy this case, x must be equal to –2.

Example Question #1563 : Gre Quantitative Reasoning

If〖7/8〗n= √(〖7/8〗5),then what is the value of n?

 

Possible Answers:

25

2/5

√5

1/5

5/2

Correct answer:

5/2

Explanation:

7/8 is being raised to the 5th power and to the 1/2 power at the same time. We multiply these to find n.

Example Question #2 : How To Multiply Exponents

Simplify: (x3 * 2x4 * 5y + 4y2 + 3y2)/y

Possible Answers:

None of the other answers

10x7 + 7y3

10x7 + 7y

10x11 + 7y3

10x7y + 7y2

Correct answer:

10x7 + 7y

Explanation:

Let's do each of these separately:

x3 * 2x4 * 5y = 2 * 5 * x* x* y = 10 * x7 * y = 10x7y

4y2 + 3y2 = 7y2

Now, rewrite what we have so far:

(10x7y + 7y2)/y

There are several options for reducing this.  Remember that when we divide, we can "distribute" the denominator through to each member.  That means we can rewrite this as:

(10x7y)/y + (7y2)/y

Subtract the y exponents values in each term to get:

10x7 + 7y

Example Question #1568 : Gre Quantitative Reasoning

Compare  and .

Possible Answers:

The answer cannot be determined from the information given.

Correct answer:

Explanation:

To compare these expressions more easily, we'll change the first expression to have  in front. We'll do this by factoring out 25 (that is, ) from 850, then using the fact that .

When we combine like terms, we can see that . The two terms are therefore both equal to the same value.

Example Question #1569 : Gre Quantitative Reasoning

Which of the following is equal to ?

Possible Answers:

Correct answer:

Explanation:

 is always equal to ; therefore, 5 raised to 4 times 5 raised to 5 must equal 5 raised to 9.

 

is always equal to . Therefore, 5 raised to 9, raised to 20 must equal 5 raised to 180.

Example Question #3 : How To Multiply Exponents

Which of the following is equal to ?

Possible Answers:

Correct answer:

Explanation:

First, multiply inside the parentheses: .

Then raise to the 7th power: .

Example Question #21 : Exponential Operations

Simplify:

(6x^{2})^{3}\cdot x^{-7}\cdot 2x^{4}

Possible Answers:

6x^{2}

12x^{2}

Correct answer:

Explanation:

Remember, we add exponents when their bases are multiplied, and multiply exponents when one is raised to the power of another. Negative exponents flip to the denominator (presuming they originally appear in the numerator). 

(6x^{2})^{3}\cdot x^{-7}\cdot 2x^{4}

 

Example Question #22 : How To Multiply Exponents

Evaluate:

Possible Answers:

\dpi{100} \small 81

\dpi{100} \small 78

\dpi{100} \small 30

\dpi{100} \small 24

\dpi{100} \small 27

Correct answer:

\dpi{100} \small 78

Explanation:

Can be simplified to: 

Capture2

Example Question #21 : Exponents

Possible Answers:

Correct answer:

Explanation:

When multplying exponents, we need to make sure we have the same base.

Since we do, all we have to do is add the exponents.

The answer is 

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