The points ( - 8, - 6) and ( - 4, s) fall on a line with a slope of 4. What is the value of s?
We have
4 = [ -6 - s ] / [ -8 - (-4) ]
4 = [-6 - s ] / [-4] multiply both sides by -4
-16 = -6 - s add 6 to both sides
-10 = -s multiply through by -1
10 = s
