Répondre :
C(x)=12x²-8x
= 4x(3x-2)
D(x)=9+27x
=9(1+3x)
B(x)=(4x-1)(-3x+2)
= -12x²+8x+3x-2
=-12x²+11x-2
A(x)= 3x²-(5x+2x²-8)+(3x²-7x+9)
=3x²-5x-2x²+8+3x²-7x+9
=4x²-12x+17
= 4x(3x-2)
D(x)=9+27x
=9(1+3x)
B(x)=(4x-1)(-3x+2)
= -12x²+8x+3x-2
=-12x²+11x-2
A(x)= 3x²-(5x+2x²-8)+(3x²-7x+9)
=3x²-5x-2x²+8+3x²-7x+9
=4x²-12x+17