Bonsoir
Exercice 121
a)
(x+4)² = (2x-1)²
(x+4)² - (2x -1)² = 0 forme de a²-b² =(a-b)(a+b)
(x+4-2x+1)(x+4+2x-1) = 0
(-x+5) (3x+3) = 0 si un des facteurs =0
-x +5 = 0 si x = 5
3x+3 = 0 si x = -1
b)
2x(x-4) = (x+1)(x-4)
2x(x-4) - (x+1)(x-4) = 0 factorisation
(x-4)( 2x - x-1) = 0
(x-4)(x-1) = 0 si un des facteurs = 0
x-4 = 0 si x = 4
x-1 = 0 si x = 1
