Sagot :
Bonjour
a) (2x + 1)(x - 3) = 0
2x + 1 = 0 ou x - 3 = 0
2x = - 1 x = 3
x = - 1/2
b) (3 - 2x)(5x + 4) = 0
3 - 2x = 0 ou 5x + 4 = 0
- 2x = - 3 5x = - 4
x = 3/2 x = 4/5
c) (3 - 2x) + (5x + 4) = 0
3 - 2x = 0 ou 5x + 4 = 0
- 2x = - 3 5x = - 4
x = 3/2 x = - 4/5
d) 4x² - 3x = 0
x (4x - 3) = 0
x = 0 ou 4x - 3 = 0
4x = 3
x = 3/4.
Bonjour,
Résoudre :
/!\ Un produit est nul si et seulement si au moins un de ses facteurs est nul
A. (2x + 1)(x - 3) = 0
A. 2x + 1 = 0 ; x - 3 = 0
A. 2x + 1 - 1 = 0 - 1 ; x - 3 + 3 = 0 + 3
A. 2x = -1 ; x = 3
A. x = -1/2 ; x = 3
A. S = { -1/2 ; 3 }
B. (3 - 2x)(5x + 4) = 0
B. 3 - 2x = 0 ; 5x + 4 = 0
B. 3 - 2x + 3 = 0 + 3 ; 5x + 4 - 4 = 0 - 4
B. 2x = 3 ; 5x = -4
B. x = 3/2 ; x = -4/5
B. S = { 3/2 ; -4/5 }
C. (3 - 2x) + (5x + 4) = 0
C. 3 - 2x + 5x + 4 = 0
C. 7 + 3x = 0
C. 7 + 3x - 7 = 0 - 7
C. 3x = -7
C. x = -7/3
C. S = { -7/3 }
D. 4x² - 3x = 0
>> facteur commun
- x
D. x(4x - 3) = 0
D. x = 0 ; 4x - 3 = 0
D. x = 0 ; 4x - 3 + 3 = 0 + 3
D. x = 0 ; 4x = 3
D. x = 0 ; x = 3/4
D. S = { 0 ; 3/4 }
Bonne journée.