Nine more than 3 times a number is the same as 6 less than twice the number

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 .

Aline passes through (1,-5) and(-3,7) write an equation for the line in point slope form rewrite the equation in slope intercept form

Ihonestly have no clue if it's each or none.