x(x+1)³+x(x+1)²+x(x+1)+x+1
=[x(x+1)³+x(x+1)²]+[x(x+1)+(x+1)]
=x(x+1)²(x+2)+(x+1)²
=(x+1)²(x²+2x+1)
=(x+1)²(x+1)²=(x+1)⁴
把多项式x(x+1)³+x(x+1)²+x(x+1)+x+1分解因式
x(x+1)³+x(x+1)²+x(x+1)+x+1
=[x(x+1)³+x(x+1)²]+[x(x+1)+(x+1)]
=x(x+1)²(x+2)+(x+1)²
=(x+1)²(x²+2x+1)
=(x+1)²(x+1)²=(x+1)⁴