Here's the question you clicked on:
MathSofiya
Find a power series rep for the function and determine the interval of convergence: \[f(x)= \frac{1}{x+10}\] \[f(x)=\frac{1}{10}*\frac{1}{1-(-\frac{x}{10})}\] \[\sum_{n=1}^{\infty} \frac{1}{10} (-\frac{x}{10})^n\] \[\sum_{n=1}^{\infty} \frac{1}{10} (-1)^n\frac{x^n}{10^n}\] \[r=\frac{x}{10}\] \[|\frac{x}{10}|<1\] \[-10<x<10\] R=10 I believe this is correct
and again, I believe you are right :)