Question

Find the first four terms of an ap in which the sum of n terms is 7n-5?​

Answer 1

Answer:

Step-by-step explanation:

Sn= 7n-5

sum of one terms = 7 x 1 - 5 = 2

we sum of one term is itself the first term

sum of two terms = 7 x 2 - 5= 9

hence the second term = ( sum of 2 terms ) - 1st term

                                         = 9-2 = 7

first term = 2

second term = 7

common difference= 5

first four terms are

2, 7, 12, 17