Question

Help anyone please i need it

Answer 1

Answer:

The sum is equal to $-905,200$

Step-by-step explanation:

we know that

The formula to calculate the sum is equal to

$Sn=n\frac{(a1+an)}{2}$

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

$Sn=775\frac{(-7-2,329)}{2}=-905,200$