x的三次方减3x^2+4x+4的因式分解

Question

x的三次方减3x^2+4x+4的因式分解

Answer 1

x的四次方加x的三次方减3x的平方减4x减4=(x^4-3x²-4)+(x³-4x)=(x²+1)(x²-4)+x(x²-4)=(x²-4)(x²+1+x)=(x+2)(x-2)(x²+x+1)