Bonsoir
1. développer les expressions :
a. x²-4(3-x)²
a. x² - 4 ( 9 - 6x +x²)
a = x² - 36 + 24x - 4x²
a = -3x² +24x -36
b. 2x(3-x)-(x-3)²
b = 6x - 2x² - (x² -6x +9)
b = 6x -2x² -x² +6x -9
b = -3x² +12x -9
Factoriser les expressions
a .2x(3-x)-(x-3)²
a = 2x(x-3)-(x-3) (x-3)
a = (x-3) (2x) - (x-3)
a = (x-3)(2x-x+3)
a = (x-3)(x+3)
b. 5x²-125
b = 5(x² - 25)
b = 5(x-5)(x+5)
c. x²-36+(4x-24)
c = (x-6)(x+6) +4 (x -6)
c = (x-6)(x+6 +4)
c = (x-6)(x+10)
