Infinite geometric series problem

MillerGenuine
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Homework Statement



\sum_{n=1}^\infty \frac{(-3)^{n-1}}{4^n}



The Attempt at a Solution



\sum_{n=1}^\infty \frac{(-3)^n-1}{4^n}


\frac{1}{4}\sum_{n=1}^\infty \frac(-{3}{4})^{n-1}


Can some one please explain how they got from the first step to the 2nd. How do you pull out a 1/4 and how does the "n" on the 4 dissapear?
Thanks
 
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