(2x²+ax-y)-(2bx²-3x+5y-1)
=2x²+ax-y-2bx²+3x-5y+1
=(2-2b)x²+(a+3)x-6y+1
其值值与字母X的值无关,x², x的系数为0
则2-2b=0
a+3=0
解得b=1 a=-3