计算:1m+3+6m2-9的结果是()A.1m-3B.m-3C.1m+3D.m+3-数学

题目简介

计算:1m+3+6m2-9的结果是()A.1m-3B.m-3C.1m+3D.m+3-数学

题目详情

计算:
1
m+3
+
6
m2-9
的结果是(  )
A.
1
m-3
B.m-3C.
1
m+3
D.m+3
题型:单选题难度:偏易来源:不详

答案

原式=class="stub"1
m+3
+class="stub"6
(m+3)(m-3)

=class="stub"m-3
(m+3)(m-3)
+class="stub"6
(m+3)(m-3)

=class="stub"m-3+6
(m+3)(m-3)

=class="stub"m+3
(m+3)(m-3)

=class="stub"1
m-3

故选A.

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