Question

Help anyone please i need it

Answer 1

The sum is equal to
`-905,200`

Explanation:

we know that

The formula to calculate the sum is equal to

`Sn=n((a1+an))/(2)`

In this problem

`n=775` -----> number of terms

a1 is the first term

`a1=(-3(1)-4)=-7`

an is the last term

`an=(-3(775)-4)=-2,329`

substitute

`Sn=775((-7-2,329))/(2)=-905,200`