The given figure is a trapezoid. Fiven that line UV is a midpoint, we would find UV by applying the midsegment property which states that
UV = 1/2(WX + ZY)
Given that
WX = x + 7
UV = 8x - 3
ZY = 6x + 5, then
8x - 3 = 1/2(x + 7 + 6x + 5)
2(8x - 3) = (x + 7 + 6x + 5)
16x - 6 = x + 6x + 7 + 5
16x - x - 6x = 7 + 5 + 6
9x = 18
x = 18/9
x = 2
Therefore
UV = 8x - 3 = 8 * 2 - 3 = 16 - 3
UV = 13