Question 551097: Find three arithmetic means between -2 and 12.
Found 2 solutions by Edwin McCravy, mathstutor458:
Answer by Edwin McCravy(20055)   (Show Source):
You can put this solution on YOUR website!
-2, ____, ____, ____, 12
If the common difference is d, then to get the next term,
we just add d each time. So to fill in the blanks:
-2, -2+d, -2+2d, -2+3d, -2+4d=12
Solve the last equation
-2+4d = 12
4d = 14
d = 
d = 
-2, -2+, -2+2 , -2+3, 12
-2,  +, + , -+ , 12
-2,  ,  ,  , 12
-2, , 5, , 12
So the three arithmetic means between them are , 5, and
Edwin
Answer by mathstutor458(57)  (Show Source):
You can put this solution on YOUR website! first number = -2
fifth number = 12
because we need to find three arithmaetic means between -2 and 12.so, totally we get 5 numbers.
this is a arithmatic series,numbers must be -2,-2+d,-2+2d,-2+3d,-2+4d
-2+4d must be equal to 12 because it is fifth number
-2+4d=12
4d=12+2=14
d=14/4=7/2=3.5
second term = -2+d=-2 + 3.5 = 1.5
third term = -2+2d = -2+2*3.5= -2+7=5
fourth term= -2+3d = -2+3*3.5 = -2+10.5=8.5
Therefore the series is -2,1.5,5,8.5,12
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