E=(3x+2)*au carré)-(3x+2)(x+7) a. développer et réduire e b.factoriser e c.calculer E pour x =1%2

E = (3x+2)²-(3x+2)(x+7)
E = (9x²+12x+4)-(3x²+21x+2x+14=
E = 9x²+12x+4-3x²-23x-14
E = 6x²-11x-10

b)
E = (3x+2)²-(3x+2)(x+7)  on met 3x+2 en facteur
E = (3x+2)(3x+2-x-7)
E = (3x+2)(2x-5)

c) x = 1/2
E = 6x1/4-11/2-10
E =3/2-11/2-20/2
E = 3/2-31/2
E = -28/2
E = -14