x^2+{(3y-2)-(2y-3)}x-(3y-2)(2y-3)=(x+3y-2)(x-2y+3)
十字相乘法
x (3y-2)
╳
x -(2y-3)谢谢，我在书上还看到了一个：(x+3y)(x-2y)+[3(x+3y)-2(x-2y)]-2*3=(x+3y-2)(x-2y+3)这个是怎么来的呢也是十字相乘法(x+3y)(x-2y)+[3(x+3y)-2(x-2y)]-2*3=(x+3y-2)(x-2y+3) (x+3y) -2 ╳(x-2y)3