bjr

33

4(x-5) = 4*x + 4*(-5) = 4x - 20

et

6 (-x+2) = 6*(-x) + 6*2 = -6x + 12

et donc 4x - 20 = -6x + 12

4x + 6x = 12 + 20

10x = 32

x = 32/10

x = 3,2

34

3 (7-2x) - 5(2x+1) = 0

3*7 + 3*(-2x) - 5*2x - 5*1 = 0

21 - 6x - 10x - 5 = 0

-16x = -16

x = 1