SAT Math Multiple Choice Practice Question 197: Answer and Explanation

Next steps

Question: 197

21. If (x + 1)2 = 64, then x could be

A. -8
B. -7
C. 7
D. 8
E. 9

Correct Answer: C

Explanation:

C. You know that when you square x + 1, you get 64, so x + 1 must equal 8 or -8. Set up two equations: x + 1 = 8 and x + 1 = -8. Solving those equations for x, you get x = 7 and x = -9. Because -9 is not one of the solutions offered, (C) must be the right choice.

If you're totally stumped by a problem like this one, you can always plug in the answer choices to see which one works!

Previous       Next