(2x^2+ax-y-b)-(2bx^2-3x+5y-1)
=(2-2b)x^2+(a+3)x-6y+1-b
由于原式与x无关,则有x的系数为0
得 2-2b=0和a+3=0
得 b=1和a=-3
则
2a^2-ab+3b^2
=2*9-3+3*1
=18
(2x^2+ax-y-b)-(2bx^2-3x+5y-1)
=(2-2b)x^2+(a+3)x-6y+1-b
由于原式与x无关,则有x的系数为0
得 2-2b=0和a+3=0
得 b=1和a=-3
则
2a^2-ab+3b^2
=2*9-3+3*1
=18