x^2+3x-(a^2+a-2)
问题描述：
x^2+3x-(a^2+a-2)
x^2-4xy+3y^2-x-y-2
答
1.x^2+3x-(a^2+a-2)=x^2+3x-(a+2)(a-1)=x^2+[(a+2)-(a-1)]x-(a+2)(a-1)=[x-(a-1)][x+(a+2)]=(x-a+1)(x+a+2) 2.x^2-4xy+3y^2-x-y-2 =x^2-(4y+1)x+3y^2-y-2=x^2-(4y+1)x+(y-1)(3y+2)=(x-y+1)(x-3y+2)