Precalculus Examples

$f (x) = {\begin{cases} 2 x - 7 & 1 \leq x < 5 \\ 4 & x = 5 \\ - 4 & x > 5 \end{cases}$ Find $f (5)$

Step 1

Identify the piece that describes the function at $x = 5$ . In this case, $x = 5$ falls within the interval $x = 5$ , therefore use $4$ to evaluate $f (5)$ .

$f (x) = {\begin{cases} 2 x - 7 & 1 \leq x < 5 \\ 4 & x = 5 \\ - 4 & x > 5 \end{cases}$

Step 2

The function is equal to $4$ at $x = 5$ .

$f (x) = 4 (]_{x = 5}^{})$

Step 3

Evaluate the function at $x = 5$ .

$f (5) = 4$