x的四次方+2x的平方+x-2
=x^4-1+2x²+x-1
=(x²+1)(x+1)(x-1)+(x+1)(2x-1)
=(x+1)[(x+1)(x²+1)+2x-1]
x的平方-2xy-35y的平方
=(x-7y)(x+5y)
（2x+1)的平方-4（2x+1)-5
=(2x+1-5)(2x+1+1)
=4(x-2)(x+1)