One question, if you don’t know, don’t answer.

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 .

Which of the following is true for the relation f(x)=2x^2+1

Which ordered pair is a solution to the system of linear equations? 2x + 3y= 6 –3x + 5y = 10