Test the Series for Convergence or Divergence $$\sum _ { k = 1 } ^ { \infty } \frac { ( - 6 ) ^ { k + 1 } } { 7 ^ { 2 k } }$$

Test the series for convergence or divergence.
$$\sum _ { k = 1 } ^ { \infty } \frac { ( - 6 ) ^ { k + 1 } } { 7 ^ { 2 k } }$$