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CGP EDU Academic Team
Published on: August 14, 2026
If x,| x + 1| and |x – l|are the first three terms of an arithmetic progression, then its sum upto 20 terms is
Text Solution
Verified by ExpertsThe correct answer is:
B
180 or 350
2|x + l| = x+ |x- 1|
(i) Case-1 :-
x
-l
2 (-x - 1) = x + (-x + 1)
-2x - 2 = 1

ThentheA.P.is
......

(ii)Case-II:-

2 (x + 1) = x + (-x + 1)
2x + 2 = 1
x = - 
ThentheA.P.is
......
[-1 + 19 x 1] = 10 x 18 = 180
(ii) Case- III :-

2(x + l) = x + x-l
2x + 2=2x-1
2 = -1
(not possible)
Hence, the required sum is 350 or 180
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