Converting LHS so it would equal to RHS?

can someone help me in converting the first equation so it would equal to the second equation:

LHS = k^2 * (2k^2 - 1 ) + [ 2k + 1 ]^3
RHS = (k+1)^2 [ 2(k+1)^2 -1 ]


i have tried many different ways but had no success so please help me!!
thanks in advance! :)
Update: THANKS FOR BOTH OF THE ANSWER!! :)
2 answers 2