Bonjour Halimatraore30
E = (x - 3)² + (x - 3)(1 - 2x)
a) Développer et réduire.
E = (x - 3)² + (x - 3)(1 - 2x)
E = (x² - 6x + 9) + (x - 2x² - 3 + 6x)
E = x² - 6x + 9 + x - 2x² - 3 + 6x
E = -x² + x + 6
b) Factorisation.
E = (x - 3)² + (x - 3)(1 - 2x)
E = (x - 3)(x - 3) + (x - 3)(1 - 2x)
E = (x - 3)[(x - 3) + (1 - 2x)]
E = (x - 3)(x - 3 + 1 - 2x)
E = (x - 3)(-x - 2)
c) Résoudre l'équation E = 0
E = 0
(x - 3)(-x - 2) = 0
x - 3 = 0 ou -x - 2 = 0
x = 3 ou -x = 2
x = 3 ou x = -2