Réponses

2014-04-01T22:48:18+02:00
n+40=2*(14+n)
n+40 = 28 + 2n
40 - 28 = 2n-n
n=12
40 = 2 (14 +n)
40 = 28 + 2n
2n = 40 -28
2n = 12
tu as perdu un n en cours de route !
2n-n = 40-28
oui, donc n=12 et non pas 2n=12
n= 12 !
2014-04-01T22:50:36+02:00
N+40=2*(14+n)
n=-40+28+2n
-2n+n= -12
-n=-12
n= -12 : -1
n= 12

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