Question

given the function
$f(x) = \

$$\begin{cases} 9x + 5 & x < 0 \\\\ 9x + 10 & x \\geq 0 \\end{cases}$$

$
evaluate the following:
$f(-1) = \square$
hint: identify the input value. determine if the input less than zero, or greater than or equal to zero.
$f(0) = \square$
$f(2) = \square$
question help: \video

Explanation:

Step1: Evaluate $f(-1)$

Since $-1 < 0$, use $f(x)=9x+5$.

$$\begin{align*} f(-1)&=9(-1)+5\\ &=-9+5\\ &=-4 \end{align*}$$

Step2: Evaluate $f(0)$

Since $0 \geq 0$, use $f(x)=9x+10$.

$$\begin{align*} f(0)&=9(0)+10\\ &=0+10\\ &=10 \end{align*}$$

Step3: Evaluate $f(2)$

Since $2 \geq 0$, use $f(x)=9x+10$.

$$\begin{align*} f(2)&=9(2)+10\\ &=18+10\\ &=28 \end{align*}$$

Answer:

$f(-1) = -4$
$f(0) = 10$
$f(2) = 28$