You would have 10 muffins left because 1/3 of 15 is 5 so 15-5=10
Since they are the conjugates of each (9-a and 9+a are conjugates, or with any number replacing 9) , we multiply it by (9+i)/(9+i) to get (9+i)^2/(9-i^2)=(81+2i+i^2)/(9-(-1))=(81-1+2i)/(10)=80/10+2i/10=8+i/5. Conjugates work because they make i into i^2 (-1) without any of the sneaky i's in the middle!
So first you plug 6 into the equation which is 4(6)-10.
Using PEMDAS, you solve what’s in the parenthesis first and you get 24-10.
24-10=14
f(6)=14