Questions

Find the common difference and first term of an arithmetic series if the sum of the first 6 terms and 9 terms are 183 and 369 respectively.

Find the sum of the series: $\rm - 8 - 6 - 4 - 2 + 0 + 2 + \dots + 40$.

Find the sum of the series: $\rm - 15 - 5 + 5 + \dots + 115$

Find the sum of the series: $\rm 7 + 10 + 13 + 16+ \dots + 67$.

Find the sum of the series: $\rm 9 + 11 + 13 + \dots + 99$.

Find the sum of the series: $\rm \sum_{n=4}^{12}(5n - 4) $.

Find the sum of the series: $\rm \sum_{n=4}^{12}(3n + 2) $.

Find the sum of the series: $\rm \sum_{n=3}^{10}(n+ 6) $.

Find the sum of the series: $ \sum_{n=1}^{11}(n+7) $.

Calculate the sum of 20 terms of the series whose $\rm n^{th}$ terms is: $\rm 8 - n$.