<PRE><B>Question 956094</B>
&lt;pre&gt;
9 and -1944

The sequence is

a&lt;sub&gt;1&lt;/sub&gt;, a&lt;sub&gt;2&lt;/sub&gt;, a&lt;sub&gt;3&lt;/sub&gt;, a&lt;sub&gt;4&lt;/sub&gt;

where the two middle terms are the two geometric means.

Using the formula for the nth term

a&lt;sub&gt;1&lt;/sub&gt;, a&lt;sub&gt;1&lt;/sub&gt;r, a&lt;sub&gt;1&lt;/sub&gt;r², a&lt;sub&gt;1&lt;/sub&gt;r³

a&lt;sub&gt;1&lt;/sub&gt; = 9, 

So the sequence is

9, 9r, 9r², 9r³

a&lt;sub&gt;4&lt;/sub&gt; = 9r³ = -1944
      r³ = -216
       r = -6

The two means are 9r and 9r², which are

           9(-6) = -54 and 9(-6)² = 9(36) = 324 

Edwin&lt;/pre&gt;



                                   

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