Well, I'm not going to do your work for you. If you really have no idea what to do, you might want to try to find a tutorial online. I found this on Google, it covers addition and subtraction of rational expressions towards the bottom.
For your problem, note that our lowest common denominator is We need to get this denominator in both fractions. To do that, we should multiply the numerator and denominator of the first fraction by and we multiply the numerator and denominator of the second fraction by