Bonjour,
A=4x-(2-x)(x+3)
=4x-(2x+6-x²-3x)
=4x-(-x²-x+6)
=4x+x²+x-6
=x²+5x-6
B=3(x-2)(2x+5)
=(3x-6)(2x+5)
=6x²-12x+15x-30
=6x²+3x-30
C=5x-(x+1)(6x-2)
=5x-(6x²+6x-2x-2)
=5x-(6x²+4x-2)
=5x-6x²-4x+2
= -6x²+x+2
D=x(x-1)(x+2)
=(x²-x)(x+2)
=x³-x²+2x²-2x
=x³+x²-2x