Question

Find the slope of a line containing points (-2,8) and (5,3).

Answer 1

(-2,8)(5,3)

slope = (y2 - y1) / (x2 - x1)
slope = (3 - 8) / (5 - (-2) = - 5/7 <==

Answer 2

slope of a line that passes through $(x_1,y_1)$ and $(x_2,y_2)$ is
$\frac{y_1-y_2}{x_1-x_2}$

given the points (-2,8) and (5,2)
the slope between them is $\frac{8-3}{-2-5}=\frac{5}{-7}=\frac{-5}{7}$

the slope is $\frac{-5}{7}$