## Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

RECALL: (1) In the slope-intercept form of a line's equation $y=mx+b$, $m$=slope and $b$ is the y-coordinate of the y-intercept. (2) Perpendicular lines have slopes whose product is $-1$ (or negative reciprocals of each other). Write both equations in slope-intercept form to obtain: First Equation: $y=-x+7$ Second Equation: $y=x+3$ Note that equations have the slopes $1$ and $-1$, respectively. Since $1 \cdot (-1) =-1$, then the graphs of the two equations are perpendicular lines.