8. A sequence \(a _ { 1 } , a _ { 2 } , a _ { 3 } , \ldots\) is defined by
$$\begin{gathered}
a _ { n + 1 } = 2 \left( a _ { n } + 3 \right) ^ { 2 } - 7
a _ { 1 } = p - 3
\end{gathered}$$
where \(p\) is a constant.
- Find an expression for \(a _ { 2 }\) in terms of \(p\), giving your answer in simplest form.
Given that \(\sum _ { n = 1 } ^ { 3 } a _ { n } = p + 15\)
- find the possible values of \(a _ { 2 }\)
| VIXV SIHIANI III IM IONOO | VIAV SIHI NI JYHAM ION OO | VI4V SIHI NI JLIYM ION OO |