\( \sum \limits_{k=1}^{\infty} \frac{(-3)^{k+2}}{13^{k}} \)
\( = -9 + \sum \limits_{k=0}^{\infty} \frac{(-3)^{k+2}}{13^{k}} \)
\( = -9 + \sum \limits_{k=0}^{\infty} \frac{(-3)^{k}\cdot 9}{13^{k}} \)
\( = -9 + 9\sum \limits_{k=0}^{\infty} (\frac{-3}{13})^{k} \)
\( = -9 + 9 \cdot \frac{1}{1-\frac{-3}{13}} = -9 + 9 \cdot \frac{13}{16} = \frac{-27}{16}\) ✓