Find the indicated sum 6 14 22 30 8n 2 6 14 22 30

Find the indicated sum. 6 + 14 + 22 + 30 + ... + (8n - 2) 6 + 14 + 22 + 30 + ... + (8n - 2) = (Simplify your answer.)

Its a A.P. = 6 +14 +22+30...(8n-2)

common difference , d = 8

a1 =6

an = 6+ 8(n-1) = 8n -2

Sum of n terms of A.P. = (n/2)(2a +(n-1)d )

= (n/2)(12 +(n-1)8 )

= (n/2)( 8n +4)

=n(4n+2)