(x+y）（x+y+10)+25=0 x-y=3.求x,y的值(x+y）（x+y-10)+25=0 x-y=3.求x,y的值
问题描述：
(x+y）（x+y+10)+25=0 x-y=3.求x,y的值
(x+y）（x+y-10)+25=0 x-y=3.求x,y的值
答
(x+y)(x+y-10)+25=0
设x+y=a
a(a-10)+25=0
a²-10a+25=0
(a-5)²=0
a=5
∴x+y=5
x-y=3
x=4 y=1