## Precalculus (6th Edition)

(a) Standard form $y=-2$ (b) Slope-intercept form $y=-2$
RECALL: (1) The standard form of a line's equation is $Ax+By=C$. (2) The slope-intercept form of a line's equation is $y=mx+b$ where $m$=slope and $(0, b)$ is the line's y-intercept. (3) Parallel lines have the same slope. (4) A line whose equation is of the form $y=k$ is horizontal and parallel to the x-axis. Every point on the line has a y-coordinate $k$. The line is parallel to the horizontal line $y=3$. This means the line is also horizontal. Since the horizontal line contains the point $(-2, -2)$, then every point on the line must have a y-coordinate of $-2$. Thus, the equation of the line is $y=-2$. (a) Standard form $y=-2$ (b) Slope-intercept form $y=-2$