The answer you are looking for is 8 7/12.
To find this answer, you must first make the denominators the same. To do so, you multiply 1/3 by 4/4 and multiply 3/4 by 3/3. This will give you 4/12 and 9/12.
The next step would be subtracting 1 (12/12) from 14 to make it 13. This is to make the numerator of 4/12 change to 16/12.
Now, you subtract. 16/12 - 9/12 = 7/12 and 13 - 5 = 8. The mixed fraction answer is 8 7/12. If you need the improper fraction answer, simply multiply 8 and 12 to get 96 and then add 96 and 7 to get 103. The denominator would still be 12, making the improper fraction form of the answer 103/12.
I hope this helps!