The points (-7,3) and (-3,r) lie on a line with slope 4 . Find the missing coordinate r.

Answer:
r = 19
Step-by-step explanation:
calculate the slope using the slope formula and equate to 4
m = [tex]\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex]
with (x₁, y₁ ) = (- 7, 3 ) and (x₂, y₂ ) = (- 3, r )
m = [tex]\frac{r-3}{-3-(-7)}[/tex] = [tex]\frac{r-3}{-3+7}[/tex] = [tex]\frac{r-3}{4}[/tex] , then
[tex]\frac{r-3}{4}[/tex] = 4 ( multiply both sides by 4 )
r - 3 = 16 ( add 3 to both sides )
r = 19