SOMEONE HELP ME PLEASE

Toyland is having a sale. all items are 20% off. how much will you save on an item that usually sells for 95$ explain your

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 .

12x + 1 = 25 solve the following equation. then place the correct number in the box provided.