Bonjour
On considère l'expression D= (3×+2)²-(3x+2)(6-4x)
a) devepper et reduire D
D = 9x² +12x +4 - (18x -12x² +12 - 8x)
D = 9x² +12x +4 -18x +12x² -12 +8x
d = 21x² +2x -8
b) factoriser D
D = (3x+2)(3x+2) - (6-4x)
D = (3x+2)(3x+2-6+4x)
D = (3x+2)(7x -4)
c) calculer D pour x = -2/3
D = ( -6/3 +2)(-14/3 -4)
D = (-6/3 +6/3)(-14/3 - 12/3)
D = 0
