I believe the equation is wrong
X=amout the shirts cost
52=8+6.50+2x
add 8 and 6.5
52=14.5+2x
subtract 14.5 from 52
37.5=2x
divide 37.5 by 2
x=18.75
It cost $18.75 for each shirt.
6(y+8) is the answer but you didn’t finish the equation so
X Coordinate: (-3a + 3a)/2
0/2 = 0
Y Coordinate: (b + b)/2
2b/2 = b
Midpoint: (calculated x, calculated y)
In this case, the midpoint should be (0, b)