<PRE><B>Question 920319</B>
Write and simplify only the specified term:

The fourth term of (x + y)^7
&lt;pre&gt;
{{{(x + y)^7}}}&lt;font face = &quot;Tohoma&quot; size = 4 color = &quot;indigo&quot;&gt; &lt;b&gt;
Use the Binomial Expansion Formula: (a + b)&lt;sup&gt;n&lt;/sup&gt; = &lt;sub&gt;n&lt;/sub&gt;C&lt;sub&gt;r-1&lt;/sub&gt; * a &lt;sup&gt;[n -(r - 1)]&lt;/sup&gt; * b &lt;sup&gt;r - 1 &lt;/sup&gt; to determine the 4th term
With a = x;  b = y  ;  r, or term number = 4; and n = 7,
(a + b)&lt;sup&gt;n&lt;/sup&gt; = &lt;sub&gt;n&lt;/sub&gt;C&lt;sub&gt;r-1&lt;/sub&gt; * a &lt;sup&gt;[n -(r - 1)]&lt;/sup&gt; * b &lt;sup&gt;r - 1 &lt;/sup&gt; becomes:
(x + y)&lt;sup&gt;7&lt;/sup&gt; = &lt;sub&gt;7&lt;/sub&gt;C&lt;sub&gt;4-1&lt;/sub&gt; * x &lt;sup&gt;[7 -(4 - 1)]&lt;/sup&gt; * y &lt;sup&gt;4 - 1 &lt;/sup&gt;
(x + y)&lt;sup&gt;7&lt;/sup&gt; = &lt;sub&gt;7&lt;/sub&gt;C&lt;sub&gt;3&lt;/sub&gt; * x &lt;sup&gt;4&lt;/sup&gt; * y &lt;sup&gt;3&lt;/sup&gt;
(x + y)&lt;sup&gt;7&lt;/sup&gt; = 35x&lt;sup&gt;4&lt;/sup&gt;y&lt;sup&gt;3&lt;/sup&gt;
&lt;/font face = &quot;Tohoma&quot; size = 4 color = &quot;indigo&quot;&gt; &lt;/b&gt;</PRE>