PSAT Math : How to add exponents

Study concepts, example questions & explanations for PSAT Math

varsity tutors app store varsity tutors android store

Example Questions

← Previous 1

Example Question #1 :Exponents

Ifa2= 35 andb2= 52 thena4+b6= ?

Possible Answers:

141,833

3929

150,000

140,608

522

Correct answer:

141,833

Explanation:

a4=a2*a2andb6=b2*b2*b2

Thereforea4+b6= 35 * 35 + 52 * 52 * 52 = 1,225 + 140,608 = 141,833

Example Question #1 :Exponents

If, what is the value of?

Possible Answers:

Correct answer:

Explanation:

Since we have two’s inwe will need to combine the two terms.

Forthis can be rewritten as

So we have.

Or

Divide this by:

Thusor

*Hint: If you are really unsure, you could have plugged in the numbers and found that the first choice worked in the equation.

Example Question #1 :How To Add Exponents

Solve for x.

23+ 2x+1= 72

Possible Answers:

5

6

3

7

4

Correct answer:

5

Explanation:

The answer is 5.

8 + 2x+1= 72

2x+1= 64

2x+1= 26

x + 1 = 6

x = 5

Example Question #481 :Algebra

Which of the following is eqivalent to 5b– 5(b–1)– 5(b–1)– 5(b–1)– 5(b–1)– 5(b–1), wherebis a constant?

Possible Answers:

1

5

1/5

0

5b–1

Correct answer:

0

Explanation:

We want to simplify 5b– 5(b–1)– 5(b–1)– 5(b–1)– 5(b–1)– 5(b–1).

Notice that we can collect the –5(b–1)terms, because they are like terms. There are 5 of them, so that means we can write –5(b–1)– 5(b–1)– 5(b–1)– 5(b–1)– 5(b–1)as (–5(b–1))5.

To summarize thus far:

5b– 5(b–1)– 5(b–1)– 5(b–1)– 5(b–1)– 5(b–1)= 5b+(–5(b–1))5

It's important to interpret –5(b–1)as (–1)5(b–1)because the –1 is not raised to the (b– 1) power along with the five. This means we can rewrite the expression as follows:

5b+(–5(b–1))5 = 5b+ (–1)(5(b–1))(5) = 5b– (5(b–1))(5)

Notice that 5(b–1)and 5 both have a base of 5. This means we can apply the property of exponents which states that, in general,abac=ab+c. We can rewrite 5 as 51and then apply this rule.

5b– (5(b–1))(5) = 5b– (5(b–1))(51) = 5b– 5(b–1+1)

Now, we will simplify the exponentb– 1 + 1 and write it as simplyb.

5b– 5(b–1+1)= 5b– 5b= 0

The answer is 0.

Example Question #1 :Exponents

Ifx^2=11, then what doesx^4equal?

Possible Answers:

Correct answer:

Explanation:

Example Question #1 :How To Add Exponents

Simplify. All exponents must be positive.

\left ( x^{-2}y^{3} \right )\left ( x^{5}y^{-4} \right )

Possible Answers:

\left ( x^{-2}+x^{5} \right )\left ( y^{3}+y^{-4} \right )

Correct answer:

Explanation:

Step 1:\left ( x^{-2}x^{5} \right )= x^{3}

Step 2:\left ( y^{3}y^{-4} \right )= y^{-1}= \frac{1}{y}

Step 3: (Correct Answer):\frac{x^{3}}{y}

Example Question #2 :Exponential Operations

Simplify. All exponents must be positive.

Possible Answers:

\frac{y^{6}}{x^{5}}

\frac{\left ( xy \right )^{2}}{\left ( xy \right )}

\frac{1}{x^{5}y^{-6}}

x^{-1}y^{4}

x^{-5}y^{6}

Correct answer:

\frac{y^{6}}{x^{5}}

Explanation:

Step 1:\frac{y^{5}}{\left ( x^{3}x^{2} \right )\left \right )y^{-1}}

Step 2:\frac{\left ( y^{5}y^{1} \right )}{x^{3}x^{2}}

Step 3:\frac{y^{6}}{x^{5}}

Example Question #7 :How To Add Exponents

\frac{\left ( -11 \right )^{-8}}{\left ( -11\right )^{12}}

Answer must be with positive exponents only.

Possible Answers:

\left ( -11 \right )^{4}

\left ( -11 \right )^{-20}

\frac{1}{\left ( -11 \right )^{20}}

\frac{1}{\left ( -11 \right )^{4}}

\left ( 1 \right )^{-20}

Correct answer:

\frac{1}{\left ( -11 \right )^{20}}

Explanation:

Step 1:\frac{1}{\left ( -11 \right )^{12}\left ( -11 \right )^{8}}

Step 2: The above is equal to\frac{1}{\left ( -11 \right )^{20}}

Example Question #1 :How To Add Exponents

Evaluate:

-\left ( -3 \right )^{0}-\left ( -3^{0} \right )

Possible Answers:

Correct answer:

Explanation:

-\left ( -3 \right )^{0}= -1

Example Question #1 :How To Add Exponents

Simplify:

Possible Answers:

Correct answer:

Explanation:

Similarly

So

← Previous 1
Learning Tools by Varsity Tutors