# How do you find f(-3) given 3-5x if x ≤0, 4x if 0<x<8, 5x+3 if x ≥ 8?

##### 1 Answer
Jul 5, 2017

See a solution process below:

#### Explanation:

Because: $- 3 \le 0$ we will use the function $f \left(x\right) = 3 - 5 x$

to solve this problem.

To find $f \left(- 3\right)$ we will substitute $\textcolor{red}{- 3}$ for each occurrence of $\textcolor{red}{x}$ in $f \left(x\right) = 3 - 5 x$

$f \left(\textcolor{red}{x}\right) = 3 - 5 \textcolor{red}{x}$ becomes:

$f \left(\textcolor{red}{- 3}\right) = 3 - \left(5 \cdot \textcolor{red}{- 3}\right)$

$f \left(\textcolor{red}{- 3}\right) = 3 - \left(- 15\right)$

$f \left(\textcolor{red}{- 3}\right) = 3 + 15$

$f \left(\textcolor{red}{- 3}\right) = 18$