What is the souloition of the fraction 6x 2(3x-9y 5) (-9)?

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 ordered pair (c,d) is a solution to the given system of linear equations- c+2d=13 -9c-4d=-15

If the scale factor between two circles is 2x/5y what is the ratio of their areas?