D.
You will multiply 3 for each visit (3dollars per visit) then just add the initial fee
The midpoint formula is ( x + x / 2, y + y / 2)
so....
6+ 2 = 8 / 2 = 4
4 + 8 = 12 / 2 = 6
the midpoint is (4, 6)
<span>4x + 8 = −2 − 2 + 5x
5x - 4x = 8 + 4
x = 12
There's only one solution, x = 12</span>