# A function f(x) is defined as f(x) = -8x^2. What is f(-3)?

$f \left(- 3\right) = - 72$
$\text{to evaluate "f(-3)" substitute "x=-3" into } f \left(x\right)$
$f \left(\textcolor{red}{- 3}\right) = - 8 \times {\left(\textcolor{red}{- 3}\right)}^{2} = - 8 \times 9 = - 72$