#### Answer

x = -6

#### Work Step by Step

Another word for zeros is the x-intercept. An x-intercept is where the line crosses the x-axis. For this to happen, the y-value must be 0, so to find the zeros of the function, the equation must equal 0.
0 = 3x + 18
Overall, we want to separate the x from all other constants. The first step would be to subtract 18 from each side.
0 - 18 = 3x + 18 - 18
This gets:
-18 = 3x
We then want to divide each side by 3 to get the x alone.
$\frac{-18}{3}$ = $\frac{3x}{3}$
This gets:
-6 = x
Since x = -6 when y = 0, x = -6 is a zero of the function.