5.
$$\frac { 6 - 5 x - 4 x ^ { 2 } } { ( 2 - x ) ( 1 + 2 x ) } \equiv A + \frac { B } { ( 2 - x ) } + \frac { C } { ( 1 + 2 x ) }$$
- Find the values of the constants \(A , B\) and \(C\).
$$f ( x ) = \frac { 6 - 5 x - 4 x ^ { 2 } } { ( 2 - x ) ( 1 + 2 x ) } \quad x > 2$$
- Using part (a), find \(\mathrm { f } ^ { \prime } ( x )\).
- Prove that \(\mathrm { f } ( x )\) is a decreasing function.