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44 votes
44 votes
What is the sum of the sereis. I dont know what to do??

What is the sum of the sereis. I dont know what to do??-example-1
User Marcothesane
by
2.9k points

1 Answer

12 votes
12 votes

Given:


\sum ^(24)_(c\mathop=1)(155-3c)

Let's evaluate the expression.

Apply the formula for summation of a conatant:


\sum ^n_(k=1)c=cn

Split the summation into smaller summations using summation rules:


\sum ^(24)_(c=1)155-3\sum ^(24)_(c=1)c

Apply the formula:


undefined

Solving further:


(155\ast24)-(-3\cdot(24(24+1))/(2))
\begin{gathered} (3720)+(-3\cdot(24(25))/(2)) \\ \\ (3720)+(-3\cdot(600)/(2)) \\ \\ (3720)+(-3\cdot300) \\ \\ 3720+(-900) \\ \\ 3720-900=2820 \end{gathered}

ANSWER:

2820

User Linus Odenring
by
3.0k points
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