Y = 500x + 38000 would be the first step, as that sets up the equation. Then, 45500 = 500x + 38000 would be the next. Third would be 7500 = 500x, as that is where we subtract 38000 from both sides. Then, finally the answer is x = 15.
To put it in a list
1. Y = 500x + 38000
2. 45500 = 500x + 38000
3. 7500 = 500x
4. 15 = x meaning 15 air conditioners must be sold