Question #N184
If $x^2 - 9 = 0$, what is the value of $x$?
A. -3
B. 3
C. -3 or 3
D. 9
Correct Answer is: C
We can factor the expression as a difference of squares: $(x+3)(x-3) = 0$. For this product to equal zero, one or both of the factors must equal zero. Therefore, $x + 3 = 0$ or $x - 3 = 0$, which gives us $x = -3$ or $x = 3$.