SOLUTION: Find the sum of the terms of the following arithmetic progressions. 6,0,-6,-12... To 100terms

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Question 884814: Find the sum of the terms of the following arithmetic progressions.
6,0,-6,-12... To 100terms
Found 2 solutions by JulietG, richwmiller:
Answer by JulietG(1812) About Me  (Show Source):
You can put this solution on YOUR website!
There is an excellent explanation along with the formula to do this here: arithmetic progression.
[Rich, I pointed this particular student to an answer to do it himself because he was rude and ill-mannered.]

Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
If you know the first and last terms use this
S = ½(A1 + An)n
If you know the first term and the difference between terms use this
S = ½(2*A1 + (n-1)d)n
We don;t know the last term
d=-6
n=100
A1=6
S = ½(2*(-6) + (99)*(-6))100
S = 50(-12 + (99)*(-6))
S = 50(-12-594)
S=50*-606
S=-30300