Développement :
A=(2X+3(X+1)+(2X-1)^2
=(2X+(3×X+3×1))+(2X×2X)-(2X×1)+(1×1)-(1×2X)
=(2X+(3X+3)+4X^2-2X+1-2X
=2X+3X+3+4X^2-2X+1-2X
=5X+1-4X^2-2X+1-2X
=4X^2 +X+1+3
=4X^2+X+4
Factorisation :
B=(2X-2)(2X-6)-(X-3)(2X-6)
=(2X-6)(X+3-2)
=(2X-6)(X+1)
C=(-X+3)(2X-1)+(-X+3)
=(-X+3)(2X)
