Not sure how to solve the last part of this problem. The original equation reads:

So then you raise the powers to get some nicer exponents to work which looks like this

and here is where I am lost, the author adds the exponents of the variables and ends up with

How is the author getting x^6/2, y^4/2 when you distribute for the first part of the equation? I am completely clueless as to how she did this could someone please fill me in. Thanks!