PSAT Math Multiple-Choice Question 448: Answer and Explanation

Question: 448

Which of the following expressions is equivalent to the expression above?

• A.
• B.
• C.
• D.

Correct Answer: B

Explanation:

B

Difficulty: Medium

Getting to the Answer: Factor out the common term p² to get p²(16m² + 72 mz + 81z²). Eliminate (D), which is equivalent until the final term. Notice that 16m² + 72 mz + 81z² is a classic quadratic:

16m² + 72 mz + 81z² = (4m + 9z)²

So the original expression is equal to p²(4m + 9z)². Thus, (B) is correct. Another way to solve would have been to FOIL, or distribute, each choice and see which one results in the given expression.