If $x=3$, which of the following expressions is an even number?
(A) $9 x$
(B) $x^{3}$
(C) $2\left(x^{2}+9\right)$
(D) $2 x^{2}+9$
(E) $3 x^{2}$
If $x=3$, which of the following expressions is even?
(A) $9 x$
(B) $x^{3}$
(C) $2\left(x^{2}+9\right)$
(D) $2 x^{2}+9$
(E) $3 x^{2}$

## Solution 1

Since the expression $2\left(x^{2}+9\right)$ contains a factor of 2 , it must be even regardless of the value of $x$.

## Solution 2

If $x=3$, then $9 x=27, x^{3}=27,2\left(x^{2}+9\right)=36,2 x^{2}+9=27$, and $3 x^{2}=27$.

Therefore, $2\left(x^{2}+9\right)$ is the only expression that is an even number.

ANSWER: (C)