For the sequence: $5, −2, −9, −16, …$

1. Find $t\left(50\right)$, the $50^{th}$ term.

   Answer (a):

   $−338$

2. Find $S\left(50\right)$, the sum of the first $50$ terms.

   Hint (b):

   $\frac{50(5+(-338))}{2}$