Hello people, I am stuck... I know I am a dumb-ass, but I have totally broken my head already. On the screen shot it is written that the first equation can be manipulated to yield the second and the third ones, but I cannot understand what has to be done in order to get the second equation from the first one! Could please somebody help me to manipulate the first equation in order to get the other ones?

 

 

AAA!!! YEAHHHH!!! Thank you my friend heaps!!!