Answer
(a) $\frac{3}{2}$
(b) $0$
(c) $undefined$
Work Step by Step
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)
$slope=\displaystyle \frac{-4-12}{6-6}$
$=\frac{-16}{0}$
$=undefined$
