Bonjour
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1x)
- 3 (2x - 5) - (5x + 3) = - 7 (3x - 7) - 5 (4 - 8x)
- 6x + 15 - 5x - 3 = - 21x + 49 - 20 + 40x
- 6x - 5x + 21x - 40x = 49 - 20 - 15 + 3
30x = 17
x = 17/30
2)
3/2 (5x - 2) - 3/4 (2x - 2/3) = 5 - (3x + 1/2)
15/2x - 6/2 - 6/4x + 6/12 = 5 - 3x - 1/2
15/2x - 3 - 3/2x + 1/6 = 5 - 3x - 1/2
15/2x - 3/2x + 3x = 5 - 1/2 + 3 - 1/6
13/2x + 6/2x = 8 - 2/6 - 1/6
19/2x = 48/6 - 3/6
19/2x = 45/6
9,5x = 7,5
x = 7,5/9,5
3)
(2x - 5) (5x - 3) - (3x - 2) (5x + 4) = 3 (x - 4) - x (3 + 5x)
10x² - 6x - 25x + 15 - (15x² + 12x - 10x - 8) = 3x - 12 - 3x - 5x²
10x² - 6x - 25x + 15 - 15x² - 12x + 10x + 8 = 3x - 12 - 3x - 5x²
10x² - 15x² + 5x² - 6x - 25x - 12x + 10x - 3x + 3x = - 12 - 15 - 8
- 21x = - 35
x = 35/21
x = 5/3.
