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> 已知xy=3,那么xyx+yxy的值是______.-数学
已知xy=3,那么xyx+yxy的值是______.-数学
题目简介
已知xy=3,那么xyx+yxy的值是______.-数学
题目详情
已知xy=3,那么
x
y
x
+y
x
y
的值是______.
题型:填空题
难度:偏易
来源:四川
答案
因为xy=3,所以x、y同号,
于是原式=x
class="stub"xy
x
2
+y
class="stub"xy
y
2
=
class="stub"x
|x|
xy
+
class="stub"y
|y|
xy
,
当x>0,y>0时,原式=
xy
+
xy
=2
3
;
当x<0,y<0时,原式=-
xy
+(-
xy
)=-2
3
.
故原式=±2
3
.
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题目简介
已知xy=3,那么xyx+yxy的值是______.-数学
题目详情
答案
于是原式=x
当x>0,y>0时,原式=
当x<0,y<0时,原式=-
故原式=±2