当a+b=3,x-y=1时,代数式a²+2ab+b²-x+y+1997的值是?

问题描述:

当a+b=3,x-y=1时,代数式a²+2ab+b²-x+y+1997的值是?

a²+2ab+b²-x+y+1997

=(a+b)²-(x-y)+1997

=3²-1+1997

=8+1997

=2005


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