What is the name of the line of reflection for the pair of figures enter your answer in the Box

Ineed asap.i cant understand this question i need someone to me right away

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 .

Question 101 points)which equation in slope-intercept form represents the line that passes through (5, 1) and(-4,7)