# How do you find f(-1) given f(x)=2x+2?

Dec 24, 2016

$f \left(\textcolor{red}{- 1}\right) = 0$

#### Explanation:

To solve $f \left(- 1\right)$ you need to substitute $\textcolor{red}{- 1}$ for every occurrence of $\textcolor{b l u e}{x}$ in the function:

$f \left(\textcolor{b l u e}{x}\right) = 2 \textcolor{b l u e}{x} + 2$

Giving:

$f \left(\textcolor{red}{- 1}\right) = \left(2 \cdot \textcolor{red}{- 1}\right) + 2$

$f \left(\textcolor{red}{- 1}\right) = - 2 + 2$

$f \left(\textcolor{red}{- 1}\right) = 0$