bonjour,
b(x) = (2x+1)²-9
C(x) = 4x²+4x-8
on factorise B(x) =
(2x+1-3)(2x+1+3)=
(2x-2)(2x+4)
on dev :
4x²+8x-4x-8 = 4x²+4x-8
A(x) = 4x²+4x-8
B(x) = (2x+1)²-9
C(x) = 4(x²+x-2)
E(x) = 0
B(x) = (x+1)²-9 = (2x-2)(2x+4)
équation produit nul
2x-2 = 0
2x =2
x = 1
2x+4 =0
2x =-4
x =-2
E(x) = -9
B(x) = (2x+1)²-9
(2x+1)²-9 = -9
(2x+1)²-9+9 =0
2x+1=0
x = -1/2
E(x) = -8
A(x) = 4x²+4x-8
à toi