ktreyb

First, we need to find the least common denominator, the lowest multiple of each number that they would share. Looking at the answer choices, they kinda give you a hint as to what it is. It's 20. This is because each number already in the denominators can be multiplied by another to equal 20.

For 6/4, we multiply both top and bottom by 5. This gives you 30/20.

For -9/5, we multiply both top and bottom by 4. This gives you -36/20.

For -1/2, we multiply both top and bottom by 10. This gives you -10/20.

Your new equation is:

30/20 - 36/20 - 10/20

OR (30 - 36 - 10) / 20

30 - 36 = -6

-6 - 10 = -16

-16/20 can be simplified by dividing both the top and bottom numbers by a greatest common factor of 4.

-4/5 is your answer, option B