Answer:
27
Step-by-step explanation:
Just add all numbers together.
Answer:
Algebraic, common difference = −9
Step-by-step explanation:
The first term of the series is 81, the second term is 72, the third term is 63 and the fourth term is 54.
So, the value of the terms decreases as the number of terms increases and this decrease in value is common and it is 9.
Therefore, the series is Algebraic series and the common difference is - 9. (Answer)
