2)1. A(x) = (2x+1)²
A(x) = 4x²+4x+1
et F(x) = 4x²+4x+1
Donc A(x) = F(x)
E(x) = (2x-1)²
E(x) = 4x²-4x+1
et C(x) = 4x²-4x+1
Donc E(x) = C(x)
D(x) = (2x+2)(x+1)-1
D(x) = 2x²+2x+2x+2-1
D(x) = 2x²+4x+1
et B(x) = 2x²+4x+1
Donc D(x) = B(x)
2.a) F(-(1/2)) = (2*(-1/2)+1)²
F(-(1/2)) = (-1+1)²
F(-(1/2)) = 0
b) B(-1) = 2*(-1)²+4*(-1)+1
B(-1) = 2-4+1
B(-1) = -1
c) C(x) = 0
(2x-1)² = 0
(2x-1)(2x-1) = 0
2x-1 = 0
2x = 1
x = 1/2
