Réponses

2014-09-05T14:34:07+02:00
3x+7*(8-x) = 60+x
3x+7*8+7*(-x) = 60+x
3x+56-7x = 60+x
-4x+56 = x+60
-4x-x+56-56 = x-x+60-56
-5x = 4
x = 4/(-5)
x = -4/5
2014-09-05T14:36:09+02:00
3x+(7fois8)-(7foisx)=60+x
3x+56-7x=60+x
-4x+56=60+x
-4x-x=60-56=4
-5x=4
x=4/-5=-4/5