## College Algebra (11th Edition)

(a) $\frac{3}{2}$ (b) $0$ (c) $undefined$
To calculate the slope between points $(x_1,y_1)$ and $(x_2,y_2)$, we use the formula: $slope=m=\frac{y_2-y_1}{x_2-x_1}$ (a) $slope=\displaystyle \frac{11-5}{5-1}$ $=\frac{6}{4}$ $=\frac{3}{2}$ (b) $slope=\displaystyle \frac{4-4}{-1--7}$ $=\frac{0}{6}$ $=0$ (c) $slope=\displaystyle \frac{-4-12}{6-6}$ $=\frac{-16}{0}$ $=undefined$