10 Let \(\mathrm { f } ( x ) = \frac { 21 - 8 x - 2 x ^ { 2 } } { ( 1 + 2 x ) ( 3 - x ) ^ { 2 } }\).
- Express \(\mathrm { f } ( x )\) in partial fractions.
- Hence obtain the expansion of \(\mathrm { f } ( x )\) in ascending powers of \(x\), up to and including the term in \(x ^ { 2 }\).