计算下列各题:(1)1x−3+69−x

问题描述:

计算下列各题:
(1)
1
x−3
+
6
9−x
1个回答 分类:数学 2014-11-12

问题解答:

我来补答
(1)
1
x−3+
6
9−x2−
x−1
6−2x;
=
2(x+3)
2(x2−9)-
12
2(x2−9)+
(x−1)(x+3)
2(x2−9),
=
2x+6−12+x2+3x−x−3
2(x2−9),
=
x2+4x−9
2(x2−9);
(2)(
x+2y
x+y−
x
y)÷(
x
y+2−
x
x−y),
=
y(x+2y)−x(x+y)
y(x+y)÷
x(x−y)+2y(x−y)−xy
y(x−y),
=
2y2−x2
y(x+y)•
y(x−y)
x2−2y2,
=-
x−y
x+y.
 
 
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