Please help and provide a detailed solution If it converges

Please help and provide a detailed solution.

If it converges, find its sum.

Thanks in advance!

Determine whether the series converges or diverges.

Solution

Since (1/3)^n converges to 1/(1-1/3)= 3/2 and (-3/4)^n converges to 1/(1+3/4)= 4/7 The series converges to 3/2-4/7= 21/14- 8/14= 13/14