Final answer:
Ethan would have a total of $75 after 5 weeks of saving.
Step-by-step explanation:
To calculate how much total money Ethan would have after 5 weeks of saving, we need to add the initial amount of money he has ($45) to the amount he saves per week ($6) multiplied by the number of weeks (5). The expression that represents the amount of money Ethan would have saved in x weeks is 45 + 6x, where x is the number of weeks. After 5 weeks, Ethan would have a total of $75.