Question

Find the value of x so that the line passing through (-2, 7) and (x, 2) has a slope of -1/3

Answer 1

Slope between (x1,y1) and (x2,y2) is (y2-y1)/(x2-x1)
we are given the points (-2,7) and (x,2)
slope is -1/3
so
(x,y)
(-2,7) and (x,2)
x1=-2
y1=7
x2=x
y2=2

slope=(2-7)/(x-(-2))=-1/3
slope=(-5)/(x+2)=-1/3
multiply both sides by (-3)(x+2) (basically cross multiply)
15=x+2
minus 2 both sides
13=x
x=13
the value of x is 13