PSAT Math Multiple-Choice Question 89: Answer and Explanation

Question: 89

Which of the following are the solutions to the equation 3x² - 48 = 0?

• A. - and
• B. -4 and 4
• C. - and
• D. -16 and 16

Correct Answer: B

Explanation:

B

The question asks for the solutions to an equation. Although the question asks for a specific value and there are numbers in the answer choices, plugging in the answers could be difficult given the lack of calculator use and the square roots. Instead, solve the equation for x. Start by adding 48 to both sides of the equation to get 3x² = 48. Next, divide both sides by 3 to get x² = 16. Then, take the square root of both sides to get x = ± 4. The correct answer is (B).