PSAT Math Multiple-Choice Question 3: Answer and Explanation

Question: 3

If , what is the value of x?

• A. 3
• B. 5
• C. 7
• D. 9

Correct Answer: B

Explanation:

B

The question asks for the value of a variable in an equation involving exponents. When dealing with questions about exponents, remember the MADSPM rules. The PM part of the acronym indicates that raising a base with an exponent to another Power means to Multiply the exponents. By the MADSPM rules, (3^x)³ = 3^3x. If 3^3x = 3¹⁵, then 3x = 15. Divide both sides by 3 to get x = 5. The correct answer is (B).