Question 1197590
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The common ratio is (-6/7); the absolute value of that ratio is less than 1, so the infinite sum exists.<br>
The formula for the sum of an infinite geometric progression is<br><pre>
            first term
  -------------------------------
   1 minus the common difference</pre><br>
The first term and the common difference are both (-6/7).  You can do the simple calculation yourself.<br>