Okay so, f(x) is another way of writing y.
If the problem were to give you an x value you would put it in the x spot.
For example:
f(x) = 1/2x - 7
is the same thing as y = 1/2x - 7
If the problem were to say: "Solve for y, if x = 2" your problem would look like this
f(2) = 1/2(2) + 7
Now, multiply 1/2 by 2, and you get 1. Now the equation is:
f(2) = 1 + 7
So add 1 and 7 = 8
so that would be f(2) = 8
And your final answer would be y = 8
I hope this helps and makes a little sense!
