An item is regularly priced at $45. it is on sale for 40% off the regular price. how much (in dollars) is discounted from the regular price?

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 .

Petes dog weighed 30 pounds it then lost 16% of it's weight how much did pete lose

Im so bad at fractions they are not my best math thing to work on