x^2+xy-6y^2= (x-2y)(x+3y)
设x^2+xy-6y^2-x-ky-6=(x-2y+a)(x+3y+b)
则a+b=-1,ab=-6,
∴a=-3,b=2或a=2,b=-3,
当a=-3,b=2时,-k=-9-4=-13,∴k=13,
当a=2,b=-3 时,-k=12,∴k=-12
x^2+xy-6y^2= (x-2y)(x+3y)
设x^2+xy-6y^2-x-ky-6=(x-2y+a)(x+3y+b)
则a+b=-1,ab=-6,
∴a=-3,b=2或a=2,b=-3,
当a=-3,b=2时,-k=-9-4=-13,∴k=13,
当a=2,b=-3 时,-k=12,∴k=-12