The 10th term of an ap is -37 and the sum of its first 6 term is minus 27 find the sum of its first 8 terms
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a10=-37
S6=-27
S6=n/2 (2a+(n-1)d)
on putting values
2a+5d=-9 ......(1)
a+(n-1)d =an
on putting values
a+9d=-37....... (2)
on solving (1), (2)
a=8
d=-5
now
S8=8/2 [2×8+(8-1)-5]
=-76ANS......
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