Question

The slope goes through (2,5) and (7,r) and equals 1/3 what is r

Answer 1

The fromula of a slope:

$m=\dfrac{y_2-y_1}{x_2-x_1}$

We have

$(2,\ 5);\ (7,\ r),\ m=\dfrac{1}{3}$

Substitute:

$\dfrac{r-5}{7-2}=\dfrac{1}{3}\\\\\dfrac{r-5}{5}=\dfrac{1}{3}\qquad|\text{cross multiply}\\\\3(r-5)=(5)(1)\qquad|\text{use distributive property}\\\\3r-15=5\qquad|\text{add 15 to both sides}\\\\3r=20\qquad|\text{divide both sides by 3}\\\\r=\dfrac{20}{3}$