WHY DOES NOBODY HELP ME PLZZ HELP

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 .

Of jk j(–25, 10) k(5, –20). is y- of l, jk a 7: 3 ? –16 –11 –4 –1

Atreasure chest sinks at a rate no less than 20 feet er second. the floor of the icean is at most at -4,200 feet. will the tresure chest reach the ocean floor in less than 3 minutes? explain.