Im bo re d so fr ee po in 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 .

Adiverr from the university of florida women’s swimming and diving team is competing in the ncaa zone b championships

Apositive number a or the same number a increased by 50% and then decreased by 50% of the result?