I am really having trouble simplifying this equation. The equation is:

(x)(y^-2)(z)/(x)(z)+(x)(y-3)=....? Sorry if it's not clear how I wrote it, hard to do on a computer without the proper symbol, but it basically reads x times y (to the power of negative 2) times z OVER(DIVIDED BY) x times z PLUS x times y (to the power of negative 3).

Now, I'm pretty sure I cannot cancel out all x's, perhaps I can subtract the y exponents from each other? I really have no idea where to start, any help is much appreciated. Tell me if you need clarification of what the problem really is and I'll try my best to explain it.