## Algebra: A Combined Approach (4th Edition)

$y=\frac{2}{9}x+3, m=\frac{2}{9}$ $y=-\frac{2}{9}x,m=\frac{2}{9}$ $\frac{2}{9}\times-1=-\frac{2}{9}$ If two lines are perpendicular the slopes are the same with a different sign(-,+) . This also means that one multiplied by -1 equals the other.