Can someone me on problems 9, 10 and 11 !

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 .

What were mkh company's cash flows from (for) operating activities in 20x1? $(180,300) $233,100 $268,200 $279,400?

The graph shown is the graph of which function?