the 7th term of an ap is 34 and the 15th term is 74. find its 40th term
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The 40th teem is either -131/259 n I'm confused u plz check over
aishwaryaboharupi:
i think it's 199
Answered by
2
a7 = 34
34=a+6d
a=34-6d.....1
a15 = 74
74=a+14d.......2
use 1 in 2
74=34-6d+14d
74=34+8d
34+8d=74
8d=74-34
8d=40
d=5
use d in 1
a=34-30
a=4
a40=a+39d
a40=4+39*5
a40=199
34=a+6d
a=34-6d.....1
a15 = 74
74=a+14d.......2
use 1 in 2
74=34-6d+14d
74=34+8d
34+8d=74
8d=74-34
8d=40
d=5
use d in 1
a=34-30
a=4
a40=a+39d
a40=4+39*5
a40=199
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