Résoudre les équations: 1°) 4(-2x + 5) = -7(3x -1) 2) 6/x = 5/7 3) (4x - 3)/5 = (3x + 2)/3 4) (3x - 5)/ (2x +6) = (6x-7)/ (4x + 18

1°) 4(-2x + 5) = -7(3x -1)
-8x+20 = -21x+7
21x-8x = 7-20
13x = -13
x = -13/13
x = -1

2) 6/x = 5/7
6*7 = 5x
5x = 42
x = 42/5

3) (4x - 3)/5 = (3x + 2)/3
3(4x-3) = 5(3x+2)
12x-9 = 15x+10
15x-12x = -9-10
3x = -19
x = -19/3

4) (3x - 5)/ (2x +6) = (6x-7)/ (4x + 18)
(3x-5)(4x+18) = (2x+6)(6x-7)
12x²+54x-20x-90 = 12x²-14x+36x-42
12x²+34x-90 = 12x²+22x-42
34x -90 = 22x-42
34x-22x = 90-42
12x = 48
x = 48/12
x = 4