第1个回答 2013-12-10
4x^2-9x-55
=(x-5)(4x+11)
2x^2-5xy-12y^2
=(x-4y)(2x+3y)
x^2+2xy+y^2-2x-2y+1
=(x+y)²-2(x+y)+1
=(x+y-1)²
x^2-4xy+4y^2-z^2-2z-1
=(x-2y)²-(z+1)²
= (x-2y+z+1)(x-2y-z-1)
x^2y^2-x^2-y^2+1
=x²(y²-1)-(y²-1)=(x²-1)(y²-1)
=(x+1)(x-1)(y+1)(y-1)
x^2-4x-xy+2y+4
=x^2-4x+4-xy+2y
=(x-2)²-y(x-2)
=(x-2)(x-2-y)