7 The sum of the first $n$ terms of an arithmetic series is $A_n$, where
$A_n = \sum_{r=1}^{n} (4r + 5)$
(a) For this arithmetic series, find
(i) the first term,
(ii) the common difference.
The sum of the first $n$ terms of a geometric series is $G_n$, where
$G_n = \sum_{r=1}^{n} 4(3)^{r-1}$
(b) For this geometric series, find
(i) the first term,
(ii) the common ratio.
(c) Find the value of $n$ for which $A_{14} - 6 = G_n$
