Archie needs to take antibiotics x times a day.
He needs to take it for a week, which is 7 days.
So the total number of antibiotics he needs is 7 * x.
Each antibiotic costs $3, so the total cost is 3 * (7 * x) = 21x.
We are given that the total cost is $63, so we can write: 21x = 63.
Dividing both sides by 21, we get: x = 3.
The value of x is 3.
#### 3
The answer is: 3
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
Archie received his medical receipt from his doctor, and he needs to take antibiotics x times a day. If antibiotic costs $3 each and he needs to take it for a week, how much money does he need to buy the antibiotics?
If we know the answer to the above question is 63, what is the value of unknown variable x?

### Answer:
