Find the sum of the first 19 terms of the AP, whose nth term is 3n+7.
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n=3n+7...
let the first term be a and common difference be d then...
a=3*1+7
a=10
A2= 3*2+7
A2=13..
d=a2-a...
d=3...
sum= n/2(2a+(n-1)d)
sum=19/2(20+18*3)
sum=19/2*74
sum=19*37
sum=703..
let the first term be a and common difference be d then...
a=3*1+7
a=10
A2= 3*2+7
A2=13..
d=a2-a...
d=3...
sum= n/2(2a+(n-1)d)
sum=19/2(20+18*3)
sum=19/2*74
sum=19*37
sum=703..
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