Given data:
The first series is 15,-14,13,-12...
The second term can be written as,
[tex]-14=15\times(-1)+1[/tex]The third term can be written as,
[tex]13=-14\times(-1)-1[/tex]The next term can be written as,
[tex]\begin{gathered} a_5=-12\times(-1)-1 \\ =11 \end{gathered}[/tex]Thus, the next term of the given series is 11.
