If a, b, c are in AP, prove that a3 + c3 + 6abc = 8b3

a3 + c3 + 6abc = 8b3
To prove: a3 + c3 + 6abc = 8b3
Given: a, b, c are in A.P.
Formula used: (a+b)3 = a3 + 3ab(a+b) + b3
Proof: Since a, b, c are in A.P.
⇒ 2b = a + c … (i)
Cubing both side,