What is the measure of ∠x?

Write an equation of the line given the two points below (write your equation in slope-intercept form, y=mx+b): (-4, 4) and (6, -4)

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 .

For f(x)=2x+1 and g(x)= x^2 -7, find (f•g)(x)