21/2 is what you should get if you divide those two
Answer:
The 21st term is 137.
Step-by-step explanation:
Arithmetic progression:
In an arithmetic progression the difference between consecutive terms is always the same, and its called common difference.
The nth term is given by:

In which
is the first term and d is the common difference.
The first two terms are -3, 4.
This means that 
So


The 21st term is

The 21st term is 137.
Surprise, there 8 letters.
So, 8*7*6*5*4*3*2*1= 40, 320