(4 x 1011) (0.9 x 10-4)

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 graph shown is the graph of which function?

The weight of an object in the water is 7% of its weight out of the water. what is the weight of a 652g object in the water?