Bonjour,
1) Résoudre les équations :
- 2 (4 - x) + 1 = 3
- 8 + 2x + 1 = 3
2x = 3 + 8 - 1
2x = 10
x = 10/2
x = 5
3 (x - 2) - 1 = - 2 (x + 4)
3x - 6 - 1 = - 2x - 8
3x + 2x = - 8 + 6 + 1
5x = - 1
x = - 1/5
- 3x + 4 = 2 (x + 2/5)
- 3x + 4 = 2x + 4/5
- 3x - 2x = 4/5 - 4
- 5x = 4/5 - 20/5
- 25/5x = - 16
- 25x = - 16
x = 16/25
2) Développer et réduire :
A (x) = 5 (2x - 3)
A (x) = 10x - 15
B (x) = (2x - 3) (- 3x - 4)
B (x) = - 6x² - 8x + 9x + 12
B (x) = - 6x² + x + 12
C (x) = (2x - 3) - (3x - 4)
C (x) = 2x - 3 - 3x + 4
C (x) = 2x - 3x - 3 + 4
C (x) = - x + 1
D (x) = (2x - 3) (4x + 2) + (2x - 3) (- 6x - 1)
D (x) = 8x² + 4x - 12x - 6 - 12x² - 2x + 18x + 3
D (x) = 8x² - 12x² + 4x + 18x - 12x - 2x - 6 + 3
D (x) = - 4x² + 8x - 3
Factoriser D (x) :
D (x) = (2x - 3) (4x + 2) + (2x - 3) (- 6x - 1)
D (x) = (2x - 3) (4x + 2 - 6x - 1)
D (x) = (2x - 3) (4x - 6x + 2 - 1)
D (x) = (2x - 3) (- 2x + 1)
