2023 CEMC Fermat Problems/Problem 3

Problem

When $x = 2$, the expression $2x^2 + 3x^2$ equals

$\text{ (A) }\ 14 \qquad\text{ (B) }\ 10 \qquad\text{ (C) }\ 12 \qquad\text{ (D) }\ 22 \qquad\text{ (E) }\ 20$

Solution 1

Plugging in $x = 2$ and following order of operations, we get:

$2 \times 2^2 + 3 \times 2^2 = 2 \times 4 + 3 \times 2^2$

$=2 \times 4 + 3 \times 4$

$=8 + 3 \times 4$

$=8 + 12$

$=\boxed {\textbf {(E) } 20}$

~anabel.disher

Solution 2

Combining like terms, we get $2x^2 + 3x^2 = 5x^2$.

Plugging in $x = 2$, we get:

$5 \times 2^2 = 5 \times 4 = \boxed {\textbf {(E) } 20}$

~anabel.disher