Question

PLEASE HELP ME I NEED THIS FAST TO PASS!!

Answer 1

*The general form of an arithmetic progression is given below as:

Sn= n/2[ 2a + ( n - 1 )• d ]

* A= is the term of the sequence

* N= is the number of term

* D= is the common difference


* Substitute the given data into the above formula


S15= 15/2 [2 (- 1 ) + (15 - 1 ) • -2 ]


S15= 7.5 [-2 - 28 ]


S15= 7.5 • (- 30 )


S15 = -225



Solution

Option B is the correct answer

Answer 2

Answer:-225

Step-by-step explanation:The arithmetic series is given by:

a1 = -1, d=-2, n = 15

where a1 is the first term, d is the common difference, and n is the number of terms.

To evaluate this series, we can use the formula for the sum of an arithmetic series:

Sn = n/2 * [2a1 + (n-1)d]

where Sn is the sum of the first n terms.

Substituting the given values, we get:

S15 = 15/2 * [2(-1) + (15-1)(-2)]

= 15/2 * [-2 - 28]

= 15/2 * (-30)

= -225

Therefore, the sum of the first 15 terms of the arithmetic series with a1 = -1, d=-2 is -225.