2/5
it is asking for f(3), so you substitute x with 3.
(4/5)3 -2
We use PEMDAS, so we start with multiplication
(12/5) - 2
now, 2 is really just 2/1
because we are subtracting, we need to make 2/1 have the same denominator as 12/5
to do this we multiply the top and bottom by 5
2/1 = 10/5
(12/5) - (10/5) = 2/5
