SOLUTION: Find the three arithmetic means between 18 and -10

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Question 36132: Find the three arithmetic means between 18 and -10
Found 2 solutions by stanbon, rapaljer:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Find the three arithmetic means between 18 and -10
a(1)=18
a(5)=18+4d=-10
4d=-28
d=-7
The missing means are
18-7=11
11-7=4
4-7=-3
Cheers,
Stan H.

Answer by rapaljer(4671) About Me  (Show Source):
You can put this solution on YOUR website!
Find the difference between the two numbers and divide by 4 (which is 1 more than 3):
%28-10-18%29%2F4=+-28%2F4+=+-7

This is the common dfference between consecutive terms. Now, start with 18 and add -7 consecutively (that is subtract 7)

Start with 18
18-7= 11
11-7=4
4-7=-3
-3-7=-10

Therefore the three arithmetic means between 18 and - 10 would be 11, 4, and -3.

R^2 at SCC
-3-7= -10