(x*x+ax-y+b)-(bx*x-3x+6y-3)
=x*x+ax-y+b-bx*x+3x-6y+3
=x*x-bx*x+ax+3x-y-6y+b+3
=(1-b)x*x+(a+3)x-y-6y+b+3
因为值与x取值无关,所以X的系数为0,即
1-b=0,则b=1
a+3=0,则a=-3