The arithmetic sequence ai is defined by the formula: a 1 =15 a i =a i-1 -7 Find the sum of the first 660 terms in the sequence.

The sum of the first 660 terms in the sequence=−1512390

Step-by-step explanation:

We are given that an arithmetic sequence

We have to find the sum of first 660 terms

Substitute i=2

Substitute i=3

Now, the common difference

Now, sum of n terms of an A.P

Substitute n=660, d=-7, a=15

Hence, the sum of the first 660 terms in the sequence=−1512390

step-by-step explanation:

i found the koficent of the linear function and i foun c acordind to the strict formula y=kx+c and then i took 2 as an x and replacet it on the formula i found and then foun the y