试题

题目:
计算:
(1)
xg
x-1
-x-1

(g)
4
+(-g008)0-(
1
3
)-1+|-g|

(3)(gabgc-3-g÷(a-gb)3
(4)
xg-yg
x
÷(x-
gxy-yg
x
)

(四)
2
xg-9
+
1
x+3

答案
解:(1)原式=
x2
x-1
-
x+1
1

=
x2
x-1
-
(x+1)(x-1)
x-1

=
x2-(x2-1)
x-1

=
1
x-1


(2)原式=2+1+3+2=个;

(3)原式(2ab2c-3-2·(a-2b)-3
=
1
4
a-2 b-4c6·a6b-3
=
1
4
a4b-7c6
=
a4c6
4b7


(4)原式=
(x+y)(x-y)
x
÷
x2-2xy+y2
x

=
(x+y)(x-y)
x
·
x
(x-y)2

=
x+y
x-y


(5)原式=
6
(x+3)(x-3)
+
x-3
(x+3)(x-3)

=
x+3
(x+3)(x-3)

=
1
x-3

解:(1)原式=
x2
x-1
-
x+1
1

=
x2
x-1
-
(x+1)(x-1)
x-1

=
x2-(x2-1)
x-1

=
1
x-1


(2)原式=2+1+3+2=个;

(3)原式(2ab2c-3-2·(a-2b)-3
=
1
4
a-2 b-4c6·a6b-3
=
1
4
a4b-7c6
=
a4c6
4b7


(4)原式=
(x+y)(x-y)
x
÷
x2-2xy+y2
x

=
(x+y)(x-y)
x
·
x
(x-y)2

=
x+y
x-y


(5)原式=
6
(x+3)(x-3)
+
x-3
(x+3)(x-3)

=
x+3
(x+3)(x-3)

=
1
x-3
考点梳理
分式的混合运算;零指数幂;负整数指数幂.
(1)把后边的两项看成一个整体,然后通分相减即可;
(2)首先计算开方,乘方、去掉绝对值符号,然后进行加减运算即可;
(3)首先利用负指数次幂的意义转化成乘法,然后进行单项式的乘法运算即可;
(4)首先计算括号内的分式,然后转化成乘法,最后计算分式的乘法即可;
(5)首先通分,然后进行分式的加减计算.
本题考查分式的混合运算,关键是通分,合并同类项,注意混合运算的运算顺序.
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