f(x)= 3+(12/(x-3)) over 2-16(x/x^2-9)
OK, let me LaTeX it so I can read it to start with...
Let's get the top and bottom to have the same denominator to start with...
And I don't like having fractions in a numerator and denominator, so let's write this as a product instead...
Expand...
Factorise everything possible...
Cancelling everything possible leaves...
There you go...