Hi guys sending this on my phone at work please tell me if its too small and ill type it out. This is the full working that I have for a derivative problem which I was fine with until the very last step. When I did it my last step involved putting the first term back into a square root and the same with the last term except in the denominator under 1.

Some factoring has happened here that I don't understand, can someone please explain to me what has happened and why between the last 2 steps? (The denominator at bottom has been cut out on uploading, it's a 3)