Help me with this bc

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 square pyramid has a volume of 441 cubic inches. what is the value of x? 1/7x is the height x is the base

Aline has a slope of . which ordered pairs could be points on a parallel line? check all that apply. (-8, 8) and (2, 2) (-5, -1) and (0, 2) (-3, 6) and (6, -9) (-2, 1) and (3,-2) (0, 2) and (5,5)