the rational function is (x+5)/(2x-4)

I have solved for the first and second derivatives and they are

f'(x)= -14/(2x-4)^2

f''(x)= 56/(2x-4)^3

In my text it gives an example of a similar question and its points of increase and decrease but it says nothing about how you solve for it using a rational function. If anyone can explain the process to me I would appreciate it. Thank you