# How do you find the value of f(-1), if f(x)=3x-4?

Mar 30, 2017

See the entire solution process below:

#### Explanation:

To evaluate $f \left(- 1\right)$ we must substitute $\textcolor{red}{- 1}$ for every occurrence of $\textcolor{red}{x}$ in the function $f \left(x\right)$:

$f \left(\textcolor{red}{x}\right) = 3 \textcolor{red}{x} - 4$ becomes:

$f \left(\textcolor{red}{- 1}\right) = \left(3 \times \textcolor{red}{- 1}\right) - 4$

$f \left(\textcolor{red}{- 1}\right) = - 3 - 4$

$f \left(\textcolor{red}{- 1}\right) = - 7$