2x²-5xy+2y²+3x-3y+1

问题描述:

2x²-5xy+2y²+3x-3y+1


2x²-5xy+2y²+3x-3y+1
=2x²+(3-5y)x+2y²-3y+1
=2x²+(3-5y)x+(1-y)(1-2y) (利用的是十字相乘法)
=(x-2y+1)(2x-y+1)