Question

Showing question 6 of 28
Write the series in summation notation:

100 + 95 + 90 + 85 + 80

Answer 1

here we have a sequence whose first term is a1=80, and 5-th term is 100, furthermore, the constant of your sequence, is:
d=100-95=95-90=90-85=85-80=...

Answer 2

furthermore the general term, namely the n-th term is:
\[\Large {a_n} = {a_1} + \left( {n - 1} \right)d\]

Answer 3

so the requested sum is:
\[\Large \sum\limits_{n = 1}^5 {{a_n}} = \sum\limits_{n = 1}^5 {{a_1} + \left( {n - 1} \right)d = ...} \]