#### Answer

y=-2

#### Work Step by Step

When an equation of a line is written in slope-intercept form, or y=mx+b form, m=slope and b=y-intercept. If the line is horizontal, then the line has a slope of zero. Therefore, m=0, and we can plug 0 in for m in the equation.
y=(0)x+b
y=b
After doing this and simplifying, we discover that y equals the y-intercept. The y-intercept is the y value where x=0, and since we know that the point (0, -2) lies on the line, we know that -2 is the y-intercept because -2 is the y value where x=0. Now we'll simply plug in -2 for b and get our equation of the line to be
y=-2