if the sum of first n terms of a sequence 25,23,19,..... is 116 .find the 8th term.
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Answer:4
Step-by-step explanation:
nswer:8
Step-by-step explanation:
D=-3
a=25
Sn=116
Sn=n/2(2a+(n-1)d)
116*2=n(50+(n-1)-3)
232=n(50-3n+3)
232=n(53-3n)
232=53n-3n^2
232+3n^2-53n=0
3n^2-53n+232=0
On solving
n=8
a8=a+7d
a8=25+7*-3
a8=25-21
a8=4
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