Réponse :
Bonjour
Exercice 2
a. 2x - 5 = 11
2x = 11+5
2x = 16
x= 16/2 = 8
b. 3x - 5 = 7 - 2x
3x+2x = 7+5
5x = 12
x= 12/5 = 2.4
c. x/2 - 7/3 = 3x - 1
x/2 -3x = -1+7/3
x/2 - 6x/2 = -3/3 + 7/3
-5x / 2 = 4/3
(-5x/2 )* 2 = 4/3 * 2
-5x = 8/3
x = (8/3) / (-5/1)
x =( 8/3) * (1/-5) (diviser par un nombre c'est multiplier par son inverse)
x = -8/15
d. 3x - 6 = 14 - 28x
3x+28x = 14 + 6
31x = 20
x= 20/31
d. 4x - 4x² - 5 + 5x = 14x + 21 - 4x² - 6
4x - 4x² + 4x² - 14x + 5x = 21 - 6 + 5
(4 -14+5)x + (4-4)x² = 20
-5x = 20
x= -(20/5)
x= -4
Bon courage!
