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if t2 = -7 and t8 = -31, what is t10 and t12? assuming the sequence is arithmetic?

 Jan 19, 2017
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 t2  =  -7  and  t8  =  -31

There are  6  'steps' between  t2  and  t8  (8 - 2  =  6).

Call the common difference 'd'.

This means that  t8  =  t2 + 6d     --->     -31  =  -7 + 6d     --->     -24  =  6d     --->     d =  -4

Thus, t10  =  t8 + 2d     --->    t10  =  -31 + 2(-4)     --->     t10  =  -39

and:   t12  =  t8 + 4d     --->   etc.   

 Jan 19, 2017

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