Question

ath term=2n+13 then that are sum of n terms

Answer 1

Answer:

a1=2+13=15

a2=2×2+13=4+13=17

Now,d=17-15=2

Sn=n/2[2×15+(n-1)2]

=n/2[30+(n-1)2]

=n[15+n-1]

=n[n+14]

=n^2+14n

Answer 2

Answer:

I think the answer is : n ( 4n + 26 + dn - d)

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Step-by-step explanation:

You use the formula : Sn = n ( a + (n - 1)d)

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