Répondre :
8x/12 + x = 8 - 8x/12 + 6 + 12 - x
8x/12 + 12x/12 + 8x/12 + 12x/12 = 8 + 6 + 12
40x/12 = 26
40x = 26*12
x = 26*12/40 = 7.8
8x/12 + 12x/12 + 8x/12 + 12x/12 = 8 + 6 + 12
40x/12 = 26
40x = 26*12
x = 26*12/40 = 7.8