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问题 解答题

关于x的一元二次方程x2+(2k-3)x+k2=0有两个不相等的实数根α，β。

（1）求k的取值范围；

（2）若α+β+αβ=6求（α-β）2+3αβ-5的值。

答案

解：（1）∵方程有两个不相等的实数根， 

      ∴△>0，即

      解得

（2）由根与系数的关系得：

         

         解得

        由（1）可知k=3不合题意，舍去

       

       故

单项选择题

以下选项中，非法的表达式是 ( )

A．'a'! =4||'b'==1

B．'a'%3

C．'a'=1/2

D．'A'+32
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单项选择题

Today’s response to the data access dilemma eschews the traditional archival approach in favor of emerging standards for what are described as the documents of the future: compound documents. Product users and developers hope the latest standards effort--such as OpenDoc and Microsoft Corp.’s Object Linking and Embedding (OLE) will (26) data accessibility.
OpenDoc is a standards group (27) a common look and feel throughout documents, even though different applications are used.
OLE technologies allow Microsoft to (28) its various software products. Microsoft creates, governs and distributes the OLE capability, which is what most (29) it from the open OpenDoc approach. Thus, users can assemble (30) of varying application to create compound documents. With OLE users can, for example, embed an Excel chart in a Microsoft word report.

A. connect B. link C. concatenate D. contact
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