Question

What comes next in the series 298,209,129,58,-4

Answer 1

$\bf \begin{array}{r|l} term&value\\ \cline{1-2} &298\\ 298-89+9(0)&209\\ 209-89+9(1)&129\\ 129-89+9(2)&58\\ 58-89+9(3)&-4\\ -4-89+9(4)&\boxed{-57} \end{array}$