Arithmetic sequence and series algebra 2

Find S10 for 2+5+8 + ...

And

Find S10 for - 1+-7+-13+-19 + ...

1: 29 2: - 55

Step-by-step explanation:

1: ... 8, 11, 14, 17, 20, 23, 26, 29 ...

2: ... - 19, - 25, - 31, - 37, - 43, - 49, - 55 ...

1: Find S10 for 2+5+8 ...

first number: 2

Common Difference: 3

nth number to obtain: 10

2: Find S10 for - 1+-7+-13+-19 ...

First number: - 1

Common Difference: - 6

nth number to obtain: 10