Answer:
r = 3
Step-by-step explanation:
Slope of a line passing through two points [tex](x_1,y_1)[/tex] and [tex](x_2,y_2)[/tex] is given by the formula,
Slope 'm' = [tex]\frac{y_2-y_1}{x_2-x_1}[/tex]
Slope of a line passing through (4, 2) and (r, -6) is 8.
8 = [tex]\frac{2+6}{4-r}[/tex]
8(4 - r) = 8
4 - r = 1
r = 4 - 1
r = 3
