2. (a) Write down the first four terms of the binomial expansion, in ascending powers of \(x\), of \(( 1 + a x ) ^ { n }\), where \(n > 2\). Given that, in this expansion, the coefficient of \(x\) is 8 and the coefficient of \(x ^ { 2 }\) is 30 ,
(b) find the value of \(n\) and the value of \(a\),
(c) find the coefficient of \(x ^ { 3 }\).