Question

the first term of an arithmetic sequence is -27. the common difference of the sequence is 6. What is the sum of the first 30 terms

Answer 1

Answer: Sum = 1800

Step-by-step explanation: I took the Test

Answer 2

1800

Explanation:

The sum to n terms of an arithmetic sequence is

`S_(n)` =
`(n)/(2)` [ 2a₁ + (n - 1)d ]

where a₁ is the first term and d the common difference

Here a₁ = - 27 and d = 6, thus

`S_(30)` =
`(30)/(2)` [ (2 × - 27) + (29 × 6) ]

= 15( - 54 + 174)

= 15(120)

= 1800