sandy wrote:
If \((x + 3)^2 = 225\), which of the following could be the value of x - 1?
(A) 13
(B) 12
(C) -12
(D) -16
(E) -19
If
something² = 225, then EITHER
something = 15 OR
something = -15
GIVEN:
(x + 3)² = 225
This means EITHER
(x + 3) = 15 OR
(x + 3) = -15
Let's examine both cases:
Case a:
(x + 3) = 15
Subtract 4 from both sides to get: x - 1 = 11
Check the answer choices . . . not there.
Case b:
(x + 3) = -15
Subtract 4 from both sides to get: x - 1 = -19
Check the answer choices . . . BINGO!
Answer: E
Cheers,
Brent
_________________
Brent Hanneson - founder of Greenlight Test Prep