Explanation:
step 1. 2c + 3e = 52, 4c + 3e = 68.
step 2. this is a system of equations. solve the system.
step 3. subtract the 1st equation from the 2nd.
step 4. 2c = 16, therefore c = 8.
step 5. 2(8) + 3e = 52. 3e = 36. e = 12.
step 6. calzones = 8, empanadas = 12.