Question

若|x+y-3|+(2x-y-5)²=0，求xy的值

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Answer 1

由题意得：Ix+y-3I=0且（2x-y-5)2=0
即x+y-3=o,2x-y-5=0
解出来的是x=8/3 y=1/3
则xy=8/9

Answer 2

|x+y-3|+(2x-y-5)²=0
|x+y-3|=0
(2x-y-5)²=0
x+y-3=0
2x-y-5=0
x+y=3
2x-y=5
3x=8
x=8/3
y=3-x=3-8/3=1/3

xy=1/3*8/3=8/9

Answer 3

x+y-3=0,2x-y-5=0,
解得x=8/3,y=1/3

Answer 4

|x+y-3|=(2x-y-5)²=0
x+y-3=0
2x-y-5=0
X=8/3
y=1/3
xy=（1/3）X（8/3）=8/9

Answer 5

等于8/9 吧··············