For the sequence: $7, −2, −11, −20, …$

1. Find $t\left(40\right)$, the $40^{th}$ term.

   Hint (a):

   $t\left(n\right) = −9n + 16$

   Answer (a):

   $t\left(40\right) = −344$

2. Find $S\left(40\right)$, the sum of the first $40$ terms.

   Hint (b):

   Use the summation formula:

   $S_{40}=\frac{40(t(1)+t(40))}{2}$