2. \(\mathrm { f } ( x ) = a x ^ { 3 } + b x ^ { 2 } - 4 x - 3\), where \(a\) and \(b\) are constants.
Given that \(( x - 1 )\) is a factor of \(\mathrm { f } ( x )\),
- show that
$$a + b = 7$$
Given also that, when \(\mathrm { f } ( x )\) is divided by \(( x + 2 )\), the remainder is 9 ,
- find the value of \(a\) and the value of \(b\), showing each step in your working.