A, x²(x-2x²)=x³-2x^4
B,(x²+1)(5-x)=5(x²+1)-x(x²+1)=5x²+5-x³-x=-x³+5x²-x+5
C, (x-2)(x²+3x-4)=x(x²+3x-4)-2(x²+3x-4)=x³+3x²-4x-2x²-6x+8=x³+x²-10x+8
D,(x-2)(x-x²-4)=x(x-x²-4)-2(x-x²-4)=x²-x³-4x-2x+2x²+8=-x³+3x²-6x+8
E,(x²-1)(x²+2x)=x²(x²+2x)-x²-2x=x^4+2x³-x²-2x
F,(2x-1)(3x+2)(3-x)=[(2x-1)(3x+2)](3-x)=(6x²-7x+2)(3-x)=(6x²-7x+2)3-x(6x²-7x+2) =18x²-21x+6-6x³+7x²-2x=-6x³+25x²-23x+6
5sao vs câu trả lời hay nhất