Precalculus Examples

$f (x) = {\begin{cases} - 2 x & x \leq - 1 \\ 1 & - 1 = 3 \end{cases}$ Find $f (- 2)$

Step 1

Identify the piece that describes the function at $x = - 2$ . In this case, $x = - 2$ falls within the interval $x \leq - 1$ , therefore use $- 2 x$ to evaluate $f (- 2)$ .

$f (x) = {\begin{cases} - 2 x & x \leq - 1 \\ 1 & - 1 = 3 \end{cases}$

Step 2

The function is equal to $- 2 x$ at $x = - 2$ .

$f (x) = - 2 x]_{x = - 2}^{}$

Step 3

Evaluate the function at $x = - 2$ .

$f (- 2) = - 2 \cdot - 2$

Step 4

Multiply $- 2$ by $- 2$ .

$f (- 2) = 4$