Question

数学题。求学霸解答

若根号X+Y-3 与根号2X-Y+6互为相反数，求X+Y的值。

Answer 1

√（x+y-3）+√（x-y-1）=0
x+y-3=0
x-y-1=0
解得
x=2
y=1

x+y=2+1=3

Answer 2

√（x+y-3）+√（x-y-1）=0
x+y-3=0
x-y-1=0
两式相加
2x-4=0
x=2
y=1
（x-y）^2=1
所以所求的平方根是1和-1

Answer 3

依题意：√x+y-3+√2x-y+6=0
则无解

Answer 4

阿富汗是 3