How to find sum of sequence?

Question

anonymous · Answer

-10, -7, -4, -1, 2, 5, 8 is the sequence I am working on.

anonymous · Answer

wouldnt it be the pattern? so in this it would be what each term is
so -10 to -7 is + what?

anonymous · Answer

$$\sum_{n=0}^{6}3n-10$$

anonymous · Answer

So would the sum be -7?

anonymous · Answer

That is one way to look at it.   You can also use the formula for finding a sum of n terms:
$$S _{n}=\frac{ n }{ 2}\left[ a _{1}+a _{n} \right]$$

anonymous · Answer

Here, n=7 (7 terms) a_1=-10 and a_n=8

anonymous · Answer

use calculator?!

anonymous · Answer

11
-70
0
-7 
are my choices. I have no clue how to do this?

anonymous · Answer

wouldnt it be the pattern? so in this it would be what each term is
so -10 to -7 is + what?

anonymous · Answer

no it is not the pattern.

anonymous · Answer

or just try adding all the numbers together

anonymous · Answer

exactly. That is why I thought it was -7

anonymous · Answer

then i would say that is your answer :D

anonymous · Answer

A pattern exists if there is a constant change from term to term.  Look at the first three terms.  What happens as you go from the first to second term.  What happens as you go from the second to third term?  The same thing happens with each succeeding term as Hope_Nicole suggests.

anonymous · Answer

However, if you just apply the formula I gave you:$$S _{7}=\frac{ 7 }{ 2}\left[ -10+8 \right]$$

Which simplifies to 

$$S _{7}=\frac{ 7 }{ 2 }\left[ -2 \right]=-7$$

anonymous · Answer

Oh okay I see. Thank you.