URM- Untitled Registered Machine

Please provide a detailed explanation so I can study this for my exam. I will upvote the answer

Write a correct URM which simulates the assignment state- ment x z without changing the original value of z. You must provide a brief coherent argument of correctness. Write a correct URM which simulates the assignment state- ment x z without changing the original value of z. You must provide a brief coherent argument of correctness