Question

Help please and explanation please

Answer 1

For this case we must add the given series. We expanded the series for each of the values of i, that is, from 1 to 5:
`3 (1) +3 (2) +3 (3) +3 (4) +3 (5) =\\3 + 6 + 9 + 12 + 15 =`

We add the terms:

`9 + 9 + 12 + 15 =\\18 + 12 + 15 =\\30 + 15 =\\45`

Finally, the value of the given series is 45.

Answer:

45