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?
答
a²+2ab+b²-x+y+1997
=(a+b)²-(x-y)+1997
=3²-1+1997
=8+1997
=2005
担心不显示平方符号,图片格式为