Write an equation to describe the sequence below. Use n to represent the position of a term in the sequence, where n = 1 for the first term.
-25/7, 75/28, -225/112, …
The general equation for the sequence is:
a(n) = (-1)^(n-1) * 25 * (3^(n-1)) / (7 * (2^(n-1)))