How do I subtract this

Ok I am in college algebra and to be honest this is NOT my strongest subject
I had a huge math problem and eventually got it down to (3/4)-(75/45). Now I am supposed to show my work. I used a calculator just to see what the answer is and it said -11/12 How do I subtract this exactly.Thank you

first 75/45 reduces to 15/9
then you need a common denominator which is 36

3/4= 27/36
15/9=60/36
subtract
27/36-60/36 (27-60)
-33/36
reduce(by 3)
-11/12

Get a common denominator for both. Then subtract and reduce the fractions.

Reduce 75/45.
(3/4) - (5/3) =
(9/12) - (20/12) =
(9-20)/12 =
-(11/12).

Ok I'm thirteen but I'm in algebra right now. You have to do the problems in () first