Intermediate Algebra (6th Edition)

We are given two lines written in the form $y=mx+b$, where m is the slope of the line and the point (0,b) is the y-intercept. $y=-9x+3$ and $y=\frac{3}{2}x-7$ In order for two lines to be parallel, they must have the same slope. However, $m=-9$ for the first line and $m=\frac{3}{2}$, so they have different slopes and cannot be parallel. Two lines are perpendicular if the product of their slopes is equal to -1. $-9\times\frac{3}{2}=-\frac{27}{2}$ Therefore, these two lines cannot be perpendicular either.