1.-10x^2z+25xyz-15y^2z =-5Z(2X^2-5XY+3Y^2)=-5Z(X-Y)(2X-3Y)
十字相乘
1 1
2 3
2.x^2+(k+2)x+(k+1)=(X+K+1)(X+1)
十字相乘
1 K+1
1 1