Aye, Khan Academy person, too :3
Okay so here's what I got:
Khan wants you to just add them. First, you should change the plus negative to a minus sign:
-5/9 - 7/12
Then, convert the fractions to have alike denominators:
-5/9 = -60/108
7/12 = 63/108
Now, you can subtract easily:
-5/9 - 7/12 = -41/36
As a mixed number: -1 5/36
Hope this helps :3
UwU
