bonsoir,
a)
4-12x = -7 -14x
4+7 = 12-14x
11 = -2x
2x = -11
x = -11/2
b)
5x/4 = 2 - 1x /4
5x/4 = 8/4 - 1x/4
5x = 8 -x
5x+x= 5
6x=8
x = 8/6 = 4/3 on simplifie par 2
c)
(x+3) /4 = (2+x) /8
2(x+3) /8 = (2+x) /8
2(x+3) = 2+x
2x+6 = 2+x
2x-x = 2-6
x = -4
d)
2x +(1/4) = (x/3) + 6
2x -x/3 = 6 -1/4
6x /3 - x/3 = 24/4 -1/4
5x/3 = 23/4
5x = 23 × 3 /4
5x= 69/4
x= 69/ 4×5
x=69/20
e)
2x/3 -1/4 = 1/5 -1/2 x
2x/3 +1x/2 = 1/5 +1/4
4x/6 + 3x/6 = 4/20 +5/20
7x /6 = 9/20x= 9×6/20×7
x = 54/140 on simplifie par 2
x = 27/70
f)
35x -70 = -6 +11x
35x -11x = 70-6
24x=64
x = 64/24 on simplifie par 8
x = 8/3
g)
7x /5 +11/7 = -8x /35 +9/7
7x/5 +8x/35 = 9/7 -11/7
49x/35 + 8x/35 = -2/7
57x /35 = -2/7
x = -2×35 / 7×57
x=-70/399 on simplifie par 7
x= - 10/57
