问题 填空题
已知三个数x,y,z满足
xy
x+y
=-2
yz
y+z
=
4
3
zx
z+x
=-
4
3
,则
xyz
xy+yz+zx
的值为______.
答案

xy
x+y
=-2,
yz
y+z
=
4
3
zx
z+x
=-
4
3

1
x
+
1
y
=-
1
2
1
y
+
1
z
=
3
4
1
z
+
1
x
=-
3
4

1
x
+
1
y
+
1
z
=-
1
4

xyz
xy+yz+zx
=
1
1
x
+
1
y
+
1
z
=-4.

故答案为:-4

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