## Intermediate Algebra (6th Edition)

We can use the slope formula to calculate the slope of a line, m, that goes through two points. $m=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}$ $m=\frac{0-2}{4-4}=\frac{0+(-2)}{0}=-\frac{2}{0}$ Any number divided by 0 is undefined, so the slope is undefined.