To set up an equation based on the problem:
- Let \( c \) be the number of cans already on the shelf.
- The total capacity of the shelf is 58 cans.
- Alexei can still put 39 cans on the shelf, which means the number of cans already on the shelf plus the 39 cans he can still add equals the total capacity of the shelf.
This can be expressed with the equation:
\[ c + 39 = 58 \]
Now, solving for \( c \):
- Subtract 39 from both sides:
\[ c = 58 - 39 \]
- Simplify:
\[ c = 19 \]
So the correct equation is \( c + 39 = 58 \) and the answer is 19.
The correct response from the options provided is:
c + 39 = 58 and 19.