bonsoir
( 9 x + 5 ) / 4 - ( - 9 x - 3 ) / 6 = ( - x + 9 ) / 2
( 27 x + 15 ) / 12 - ( - 18 x - 6 ) / 6 = ( - 6 x + 54 ) / 12
27 x + 15 + 18 x + 6 = - 6 x + 54
45 x + 6 x = 54 - 15 - 6
51 x = 33
x = 33 /51 = 11 / 17
- 7 x - 1 /7 = 4 x + 9
- 49 x / 7 - 1 /7 = 28 x /7 + 63 /7
- 49 x - 28 x = 63 + 1
- 77 x = 64
x = - 64/77