If f(x)=3x^2 then f(-2)=?

Apr 30, 2018

$f \left(- 2\right) = 12$

Explanation:

$f \left(x\right) = 3 {x}^{2}$

To find $f \left(- 2\right)$ you just need to put $- 2$ instead of $x$:

$f \left(- 2\right) = 3 {\left(- 2\right)}^{2} = 3 \cdot 4 = 12$

Apr 30, 2018

$f \left(- 2\right) = 12$

Explanation:

All we need to do here is substitute the number in parentheses ($- 2$) for $x$ in the function:

$f \left(- 2\right) = 3 {\left(- 2\right)}^{2} = 3 \left(4\right) = 12$

Note that the negative symbol from the $- 2$ is included in the parentheses for the exponent.