Question

Find the value of r so that the line through (8,r) and (4,5) has a slope of -4

Answer 1

Answer:

r = - 11

Step-by-step explanation:

Calculate the slope m using the slope formula and equate to - 4

m = $\frac{y_{2}-y_{1} }{x_{2}-x_{1} }$

with (x₁, y₁ ) = (4, 5) and (x₂, y₂ ) = (8, r)

m = $\frac{r-5}{8-4}$ = $\frac{r-5}{4}$ = - 4 ( multiply both sides by 4 )

r - 5 = - 16 ( add 5 to both sides )

r = - 11