计算(1)2xx2-4-1x-2(2)aa-1÷a2-aa2-1-1a-1.-数学

题目简介

计算(1)2xx2-4-1x-2(2)aa-1÷a2-aa2-1-1a-1.-数学

题目详情

计算
(1)
2x
x2-4
-
1
x-2

(2)
a
a-1
÷
a2-a
a2-1
-
1
a-1
题型:解答题难度:中档来源:不详

答案

(1)原式=class="stub"2x
(x+2)(x-2)
-class="stub"x+2
(x+2)(x-2)

=class="stub"2x-x-2
(x+2)(x-2)

=class="stub"1
x+2


(2)原式=class="stub"a
a-1
×class="stub"a+1
a
-class="stub"1
a-1

=class="stub"a+1
a-1
-class="stub"1
a-1

=class="stub"a
a-1

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