【这个怎么因式分解】x^2+xy-2y^2+x+5y-2≥0是怎么分解成的（x-y+2)(x+2y-1)≥0
问题描述：
【这个怎么因式分解】x^2+xy-2y^2+x+5y-2≥0是怎么分解成的（x-y+2)(x+2y-1)≥0
答
x²+xy-2y²+x+5y-2
= x²+xy-2y²-(x-y)+2(x+2y)-2
=(x-y)(x+2y) -(x-y)+2(x+2y)-2
=(x-y)(x+2y-1)+2(x+2y-1)
=(x-y+2)(x+2y-1)