What’s the midpoint of points a (6,-4) and b (2,-10) graphically

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 .

What fraction is equivalent to 0.46464646··· a. 46⁄99 b. 46⁄999 c. 46⁄100 d. 23⁄50

Y+ 2/y is it a polynomial in one variable or not? and if so, why?