1.（x^2y-xy^2)/（x-y)
=xy(x-y)/(x-y)
=xy
2.x^2-5x-+6
x^2-5x+6=(x-2)(x-3)
x^2-5x-6=(x-6)(x+1)
3.3x^2-8x+4
=3x^2-6x-2x+4
=3x(x-2)-2(x-2)
=(x-2)(3x-2)
解方程1,x^2-4x+3 =0
(x-1)(x-3)=0
x1=1,x2=3
2,2y^2-5y+2=0
(2y-1)(y-2)=0
y1=1/2,y2=2