I have no idea what you mean by "turn x into z". I would guess that you want an equation setting "z= " something to do with x. x is equal to 1825+ 9/1217 while z is equal to 1825+ 2+ 2/3. Okay, y= 7+ 2/3 so you could add y and subtract 5 to go from 1825+ 1827. Then, you would need to subtract 9/1217 to get rid of that fraction. That seems a very strange way to do a subtraction! If you were required to include that "y", you would just subtract x from z to see what needed to be added.