Im looking at this example and trying to figure out how they showed it was associative.
They start out with x*y=x+y+1
then they add in z to show it is associative.
I dont know how they go from
and end up with the equation on the right.
If i solved for x from x*y=x+y+1 and plugged it in I wouldn't get what they got.
Maybe there is some trick that I am missing.