How do you know if a line on a graph shows an additive pattern?

Iam trying to solve a linear equation for the shoe size of someone 84" tall taking into consideration example 1 is 69" tall with a shoe size of 9 and example 2 is 72 inches tall with a shoe size of 11. i understand that the equation should be y=mx+b and that on the graph the answer is (3,2) but i just don't understand how to create the equation to solve for 84-inches and 60-inches tall questions. after two days, i need .

The coordinates of a, b, and c in the diagram are a(p,4), b(6,1), and c(9,q). which equation correctly relates p and q? hint: since is perpendicular to , the slope of × the slope of = -1. a. p - q = 7 b. q - p = 7 c. -q - p = 7 d. p + q = 7

The sum of two numbers is 86, and their difference is 20. find the two numbers