SOLUTION: 1.Find the arithmetic mean between -2,___18 2.Find the sum of sequence -30,-15,0,15,30,... It's fine if you don't show the solution just the answer, thanku^^

Question 1184341: 1.Find the arithmetic mean between -2,___18
2.Find the sum of sequence -30,-15,0,15,30,...
It's fine if you don't show the solution just the answer, thanku^^
Answer by ikleyn(52790) (Show Source): You can put this solution on YOUR website!
.


1.  The arithmetic mean of the numbers -2 and 18 is half of their sum   =  = 8.



2.  Regarding your sequence, I see 5 terms there  -30, -15, 0, 15, 30.


    Then I see ellipsis, that says me nothing.



    The sum of the five written terms is equal to zero.



    If you mean something different, then take a labor to describe this "something" adequately.

--------------------

For arithmetic sequences, there are well known formulas, written everywhere, in any textbook or in numerous Internet sites.

For example, you may look into the lessons
    - Arithmetic progressions
    - The proofs of the formulas for arithmetic progressions
    - Problems on arithmetic progressions
    - Word problems on arithmetic progressions
in this site and to learn the subject from there . . .

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