2A-B
=(2b-2)y²-(5a+5)y-1
和y无关则系数为0
所以2b-2=05a+5=0
a=-1,b=1
所以原式=2a²+2ab²-2a²b+2-3ab²-2
=2a²-2ab²-2a²b
=2+2-2
=2