Answer:
r = 8
Step-by-step explanation:
Calculate the slope m using the slope formula and equate to 3
m = [tex]\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex]
with (x₁, y₁ ) = (4, - 6) and (x₂, y₂ ) = (r, 6)
m = [tex]\frac{6+6}{r-4}[/tex] = [tex]\frac{12}{r-4}[/tex] , then
[tex]\frac{12}{r-4}[/tex] = 3 ( multiply both sides by (r - 4))
12 = 3(r - 4) ← divide both sides by 3
4 = r - 4 ( add 4 to both sides )
8 = r
