The answer is (3,2). I did this by drawing a graph, inserting the two midpoints you provided, and put in each potential midpoint, finding (3,2) is the only midpoint that connects to the line.
I think its C sorry if its wrong!
The answer is 6 shirts
12.5x+8=83
12.5x=83-8
12.5x=75
x=75/12.5
x=6
The work has one step: divide the expression by 3.
.. -4 > x
Because the symbol is "greater than", the circle at x=-4 is an open circle.