What is x to the nearest tenth?

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 .

Enter the missing numbers in the boxes to complete the table of equivalent ratios of lengths to widths. ? 18 8 ? 10 30 12 ?

Graph the equation by plotting point x=2