Answer:
-5/3
Explanation:
In order to add or subtract fractions, the denominators need to be the same. In this case, the lowest common denominator would be 15abc.
So to get to that, you'll end up with 20abc/15abc - 45abc/15abc. Now you can subtract the numerators, which will give you -25abc/15abc. Once divided and simplified, your answer will be -5/3.