In this sequence there are actually two sequences. 1 sequence for the numerators and one sequence for the denominators. The following transformation applies to the sequence for the denominators : -2
This creates the following sequence: [5, 3, 1, -1, -3, -5, -7]
The following transformation applies to the sequence for the numerators: -9
This creates the following sequence: [10, 1, -8, -17, -26, -35, -44]
Take a good look at how to rewrite the fractions in the series to recognize the pattern.
For example, 1/2 can be rewritten as 5/10