Question

find the sum of first 14th terms of. an ap 3;15;27;39....​

Answer 1

Answer:

Step-by-step explanation:

n=10

given a= 3

d = 15-3= 12

sum of n terms of an ap =n/2[2a+(n-1)d]

Sn=10/2[2*3 +(10-1)12]

S=5[6+108]

S=5(114)

S=570. answer

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