Réponses

2014-05-21T20:33:54+02:00
Bonsoir
a) 2x -x = -3 -1
3x = -4
x = -4/3

b) 7x -9x = 1 +8
   -2x = 9
   x = -9/2

c) 12x +14x = -7 -4
   26x = - 11
   x = -11/26
d) -3x -x = -13 -8
- 4x = - 21
x = 21/4
e) 2x -5x = -3 -6
-3x = -9
x =3


tarif adulte = x
tarif enfant = x  -4

100x + 50( x -4) = 1300
100x + 50x - 200 = 1300
150 x = 1300 +200
150x = 1500
x = 10
tarif adulte = 10 €, enfant = 6€
tu as fais nimporte quoi au premier nullasse
il y a des choses fautes
2014-05-21T20:48:22+02:00
A) 2x+1= x-3
2x +1-1 -x= x -3 -1 -x
x=-4

b) 7x -8= 9x +1
7x -8 +8 -9x= 9x +1 +8 -9x
-2x= 9
-2x/-2= 9/-2
x= -9/2 ou -4,5 cest pareil

c) 4-12x= -7 -14x
4 -12x -4 +14x= -7 -14x -4 +14x
2x= -11
2x/2= -11/2
x= -11/2 ou -5,5 cest pareil

d) -3x +8= x-13
-3x +8 -8 -x= x -13 -8 -x
-4x= -21
-4x/-4= 21/-4
x= 21/-4 ou -5,25 cest pareil

e) 2x +6= 5x -3
2x +6 -6 -5x= 5x -3 -6 -5x
-3x= -9
-3x/-3= -9/-3
x=3

f) 3x -8= -7x +1
3x -8 +8 +7x= -7x +1 +8 +7x
10x= 9
10x/10= 9/10
x= 9/10 ou 0,9 cest pareil