Question

find the sum of first n multiples of 3

Answer 1

Answer:

3n²/2

Explanation:

a = 3; d = 3; no. of terms = n

Sum pf first n terms of an AP = n/2 {a + (n-1)d}

=> n/2 {3+3n-3}

=> 3n²/2

Hope this helps.....

Answer 2

3n²+3 check it out if it is correct