Let f(x) = x2 - 3x - 7. Find f(-3)

$${f}{\left({\mathtt{x}}\right)} = {{\mathtt{x}}}^{{\mathtt{2}}}{\mathtt{\,-\,}}{\mathtt{3}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,-\,}}{\mathtt{7}}$$

Plug in -3 for x:

$${f}{\left(-{\mathtt{3}}\right)} = {\left(-{\mathtt{3}}\right)}^{{\mathtt{2}}}{\mathtt{\,-\,}}{\mathtt{3}}{\mathtt{\,\times\,}}\left(-{\mathtt{3}}\right){\mathtt{\,-\,}}{\mathtt{7}}$$

Now simplify:

$${f}{\left(-{\mathtt{3}}\right)} = {\mathtt{9}}{\mathtt{\,\small\textbf+\,}}{\mathtt{9}}{\mathtt{\,-\,}}{\mathtt{7}}$$

$${f}{\left(-{\mathtt{3}}\right)} = {\mathtt{11}}$$