<PRE><B>Question 1106491</B>
.
&lt;pre&gt;
    The first term is {{{S[1]}}} = 9 with n = 1.


    The second term is {{{S[2]}}} - {{{S[1]}}} = 28-9 = 19.


    The third  term is {{{S[3]}}} - {{{S[2]}}} = 57-28 = 29.


That is all you need. The first three terms are 9, 19 and 29.
&lt;/pre&gt;

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On arithmetic progressions, see introductory lessons  in this site:

&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;- &lt;A HREF=http://www.algebra.com/algebra/homework/Sequences-and-series/Arithmetic-progressions.lesson&gt;Arithmetic progressions&lt;/A&gt;

&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;- &lt;A HREF=http://www.algebra.com/algebra/homework/Sequences-and-series/The-proofs-of-the-formulas-for-arithmetic-progressions.lesson&gt;The proofs of the formulas for arithmetic progressions&lt;/A&gt; 

&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;- &lt;A HREF=http://www.algebra.com/algebra/homework/Sequences-and-series/Problems-on-arithmetic-progressions.lesson&gt;Problems on arithmetic progressions&lt;/A&gt;  

&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;- &lt;A HREF=http://www.algebra.com/algebra/homework/Sequences-and-series/Word-problems-on-arithmetic-progressions.lesson&gt;Word problems on arithmetic progressions&lt;/A&gt;


Also, &amp;nbsp;you have this free of charge online textbook in ALGEBRA-II in this site

&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;- &lt;A HREF=https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson&gt;ALGEBRA-II - YOUR ONLINE TEXTBOOK&lt;/A&gt;.


The referred lessons are the part of this online textbook under the topic &lt;U&gt;&quot;Arithmetic progressions&quot;&lt;/U&gt;.



Save the link to this textbook together with its description


Free of charge online textbook in ALGEBRA-II
https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson


into your archive and use when it is needed.



</PRE>