(x-2)(x²+2x+4)=x(x²+2x+4)-2(x²+2x+4)=x³+2x²+4x-2x²-4x²-8=x³-8
(x-2)(x的平方+2x+4)=(x-2)的三次方
(x-2)(x^2+2x+4)=x^3+2X^2+4x-2x^2-4x-8=x^3-8
x^3-8
