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| Question 1208027:  Find the valee of k and the 17 term of each of the following arithmetic sequence
 6)2k+1,5k-3, 7k-2
 7) 7k+2,5k+4,4k-5
 Found 2 solutions by  mccravyedwin, ikleyn:
 Answer by mccravyedwin(408)
      (Show Source): Answer by ikleyn(52856)
      (Show Source): 
You can put this solution on YOUR website! . Find the
  value of k and the  17-th term of each of the following arithmetic sequence 6) 2k+1,5k-3, 7k-2
 7) 7k+2,5k+4,4k-5
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
 
 I will solve first part,  leaving the second part to you as an exercise,
 because the second part is a  TWIN  to the first part.
 
 
 
 
Since three terms  ,  and  form an arithmetic progression,
the difference  is the same as the difference  (as each this difference is simply d, the common difference of the AP).
So, we write
    (5k-3) - (2k+1) = (7k-2) - (5k-3).
From this equation, we find the value of k
    5k - 3 - 2k - 1 = 7k - 2 - 5k + 3,
    3k - 4 = 2k +1
    3k - 2k = 1 + 4
        k   =   5.
Now we know the value of k and can restore the values of the first three twrms of this AP  = 2*5+1 = 11;  = 5*5-3 = 22;  = 7*5-2 = 33.
Thus, the progression has first term 11 and the common difference d = 22-11 = 11.
At this point, we know everything about this AP and can easily find each of its terms.
In particular, the 17-th term of this AP is  =  + d*(n-1) = 11 + 11*(17-1) = 11 + 11*16 = 187.    ANSWER Solved.
 
 This solution is your TEMPLATE to solve many other similar problems.
 
 In particular, the other part is a TWIN and can be solved by the same way.
 
 Literally follow my solution, step by step.
 
 You may report me about your progress.
 
 
 
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