Respuesta :
The expression is ' 0 ', as in 'zero'. If it were anything else, then that wouldn't help you go back to where you started and get what you forgot.
Answer:
y = x - 5 + 5
Step-by-step explanation:
Let x be the the original position and y be the new position.
After rid down, 5 floors, the expression would be y = x - 5.
After rid back up 5 floors, the expression changed to y = x - 5 + 5.
Hence, the required expression is y = x - 5 + 5 = x.