how many terms of an AP 9,17, 25 must be taken to give a sum of 636
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Answered by
22
Answer:
answer in attachement
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rohith925:
please can u write little neatly
i. said i m sorry
but i m sure u can understand every step i m a 11th grade student so i had to do it in a haste
i touched the question as i jst wanna help u dear
listen u jst need to put value of everything i had given a and d now just we have to solve i hope u understand sorry for inconvenience
Answered by
20
Answer:
9,17,25,...
d=8
a=9
An=n/2[2a+(n-1)d]
636=n/2[2×9+(n-1)8]
1272=n(18+8n-8)
8n²+10n-1272=0
4n²+5n-636=0
n={-4±√(5)²-4.4.636}/2.4
n=(-4±101)/8
n=-4+101/8=96/8=12
thank you
welcome
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