7x+3=24 what is the value of 5-4x

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 .

One card is dealt from a 52 card deck. find the probability that the dealt card is a 4 or a black 7

Which expression gives the area of the triangle shown below