已知|x-y+3|与2（x+y）²互为相反数,求x²+2xy+y²的值．

题目

已知|x-y+3|与2（x+y）²互为相反数,求x²+2xy+y²的值．

答案

|x-y+3|与2（x+y）²互为相反数
x-y+3=0
x+y=0
x=-3/2
y=3/2
x²+2xy+y²
=(x+y)²
=0