What is the volume...no links as the answer. Please help asap this is urgent.

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 .

Plzzzz i beg u asap ! what is the equation of this graphed line? enter your answer in slope-intercept form in the box.

Determine the number of girls in a math class with 87 boys if there are 25 girls for every 75 boys