SOLUTION: Find the 89th term of the arithmetic sequence 20,10,0,...

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Question 948066: Find the 89th term of the arithmetic sequence 20,10,0,...
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
20,10,0,...

It's just a matter of plugging in the formula for the nth term:

a%5Bn%5D=a%5B1%5D%2B%28n-1%29d

first term = a1 = 20, common difference d = 10-20 = 0-10 = -10

a%5B89%5D=20%2B%2889-1%29%28-10%29=20%2B%2888%29%28-10%29=+-860

Edwin