SAT Math Question of the Day

Q: If (3 - x)(3 + x) = -16, then what is a possible answer for x?

1. -5
2. -4
3. -1
4. 4
5. 6

UNANSWERED.

The correct answer is A.

A:

One way to do this problem is to just plug in the possible answers and see which one fits the equation.

Let's try choice A, where x is -5,
(3 - x)(3 + x) = -16
(3 - -5)(3 + -5) = -16
(8)(-2) = -16
-16 = -16
IT WORKS!
So the answer is x is -5 or choice A.

Another way to solve it is algebraically:
(3 - x)(3 + x) = -16
(x - 3)(x + 3) = 16
x² - 9 = 16
x² = 25
x = 5 or -5
So, A is the correct answer.