How many terms have to be considered for getting the sum 5740 in the A.P7,14,21....?
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a=7
d=14-7
=7
Sn=n/2{2a+(n-1)d}
5740=n/2{14+(n-1)7}
5740=n/2{14+7n-7}
5740=n/2(7+7n)
11480=7n+7n²
7n²+7n-11480=0÷7
n²+n-1640=0
n²+41n-40n-1640=0
n(n+41)-40(n+41)=0
(n-40)(n+41)=0
n=40 or -41
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d=14-7
=7
Sn=n/2{2a+(n-1)d}
5740=n/2{14+(n-1)7}
5740=n/2{14+7n-7}
5740=n/2(7+7n)
11480=7n+7n²
7n²+7n-11480=0÷7
n²+n-1640=0
n²+41n-40n-1640=0
n(n+41)-40(n+41)=0
(n-40)(n+41)=0
n=40 or -41
mark me brainliest
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