Help this is urgent!!!

With #! i’ve tried to figure it out but i can’t.

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 radical equation 2+√2x-3 = √x+7 has a solution set [x= a0} and an extraneous root x = a1.