Hello guest and Alan,

sorry for coming back only now...I guess this is one of those sums that I just never will grasp, simply because:

guest stated (and Alan), I suppose, that the "y" can be canceled, because it is a common factor...okay, we can do that when we have only the variables, but when they are assigned values, it's a diferent story, because I cannot just cancel the "Y" values..so, I cannot just cancel the "7" and the "3". So we multiply with them. This gives me the result of \(15 \over14\), but this answer includes "y"..so the answer is not purely "x" and "z" only..maybe I'm over-complicating things here, but I just cannot see it.

It;s to say this: x * y = x, and y * z = z...which is not true

anycase, you guys had been helpful, I do appreciate...