Two cars started from the same point 5 am, traveling in opposite directions. The speed of one car is 40 mph and the speed of the other car is 50 mph. At what time will the cars be 450 miles apart?

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 .

Pls! does anybody know a shortcut for answering these types of questions in the future?

Which equation represents a line that is parallel to the line whose equation is 3x-2y=7( show all work)