Réponses

2014-05-06T20:36:36+02:00
7X+3-9(-2+X)
7x +3 -9*-2 -9*x
7x +3 +18 -9x
-2x +21
2014-05-06T20:38:02+02:00
7x + 3 - 9(-2 + x) = 0
7x + 3 + 18 - 9x = 0
7x - 9x + 3 + 18 = 0
-2x + 21 = 0
-2x = -21
x = 21/2
x = 10,5