Bonsoir,
- Résoudre les équations suivantes:
2x - 3 + 4x² + 7 - 5x + x²-4 = 0
4x² + x² - 5x - 3 - 4 + 7 = 0
5x² - 5x = 0
5x (x - 1) = 0
5x = 0 ou x - 1 = 0
x = 0 x = 1
(4x + 3) (2x - 1) = 0
4x + 3 = 0 ou 2x - 1 = 0
4x = - 3 2x = 2
x = - 3/4 x = 2/2
x = 1
(3x + 5)(4 + x)= 0
3x + 5 = 0 ou 4 + x = 0
3x = - 5 x = - 4
x = - 5/3
(2 - 4x)(7x - 3)= 0
2 - 4x = 0 ou 7x - 3 = 0
- 4x = - 2 7x = 3
x = 2/4 x = 3/7
x = 1/2
x² -16 = 0
(x - 4) (x + 4) = 0
x - 4 = 0 ou x + 4 = 0
x = 4 x = - 4
(2+ x) (2 -3x) = 4
(2 + x) (2 - 3x) - 4 = 0
(2 + x - 2) (2 - 3x + 2) = 0
x (- 3x + 4) = 0
x = 0 ou - 3x + 4 = 0
- 3x = - 4
x = 4/3.
- Recopier et compléter ces deux résolutions
3 ( 7x - 4 ) = 9 + 18x
21x - 12 = 9 + 18x
21x - 18x = 9 + 12
3x = 21
x = 21/3
x = 7
5( x + 6 ) – ( 2x + 6 )= 7x-1
5x + 30 - 2x - 6 = 7x - 1
5x - 2x - 7x = - 1 - 30 + 6
- 4x = - 35
x = 35/4.
