6.
$$f ( x ) = x ^ { 4 } + 5 x ^ { 3 } + a x + b$$
where \(a\) and \(b\) are constants.
The remainder when \(\mathrm { f } ( x )\) is divided by ( \(x - 2\) ) is equal to the remainder when \(\mathrm { f } ( x )\) is divided by \(( x + 1 )\).
- Find the value of \(a\).
Given that \(( x + 3 )\) is a factor of \(\mathrm { f } ( x )\),
- find the value of \(b\).