If you mean (x+9)/16 = 7/8 + (x-6)/6 then:
Multiply both sides by the LCD, 48: 3(x+9) = 42 + 8(x-6)
3x + 27 = 42 + 8x - 48
3x + 27 = 8x - 6
33 = 5x
x = 33/5 = 6.6