Explain how i do this pls ! - -7n+3= -46

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 .

In the rectangle below ac=30 units what is de

What are the solutions to the following equation? |m| = 8.5 the value of m is equal to 8.5 and because each distance from zero is 8.5.