20%x+8+（（20%x+8）*75%）+113等于x
0.2x + 8 + [ (0.2x + 8) ×0.75 ] + 113 ＝ x
0.2x + 8 + [ 0.15x + 6 ] + 113 = x
0.2x + 0.15x - x = -113 - 8 - 6
- 0.65x = - 127
x = 127/0.65 = 195又5/13