What is the GCF of 84 and 56

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 .

Avegetable garden and a surrounding path are shaped like a square that together are 11ft wide. the path is 2ft wide. find the total area of the vegetable garden and path

Iwill give ! if m∠a=59 and m∠3=81°, what is m∠b? m∠b= _[blank]_°