Maths / Arithmetic Progression / Find Last Term When First Term, Number of Terms and Sum of N Terms is Given

QUESTION
 

Find the 14th term of an AP whose first trem  x+2 and sum of 14 terms is 42x-14

OPTIONS
A. 

5x-2

B. 

7x-4

C. 

5x

D. 

5x-4

Right Option : D

EXPLANATION
Explain TypeExplanation Content
Text

large S_n = frac{n}{2}(a+l)

large dpi{120} fn_jvn large 42x-14 = frac{14}{2}(x+2 +l)

42x-14 = 7(x+2+l)

6x-2= x+2+ l

l = 6x-2-x-2 = 5x-4

 

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