Okay, so, in this problem, first you want to combine your like-terms, so, all the numbers with the variable 'f' attached to them.
-1/8f - 3/4 - 1/4f = 11
So, now your problem should look like this:
-3/8f - 3/4 = 11
Now, you do the opposite of subtraction, which is addition, and movie the -3/4 and combine it with the 11:
-3/8f - 3/4 = 11
+3/4 +3/4
______________
-3/8f = 11 3/4
Now, to find F, divide by -3/8 on both sides:
-3/8f = 11 3/4
÷ -3/8 ÷3/8
____________
F = 31 1/3
I hope this helps!
