Question 151455
First of all, there are several different methods they will teach you to solve these equations/expressions, etc.  All of the methods result in the same answer, though.

I'm not going to take you step-by-step like everyone else here, who truly understand all this stuff.  Instead, I offer something much more valuable and it's a link I keep handy on my desktop and use very often.  Go to http://www.myalgebra.com/algebra_solver.aspx and you will see that this site is an absolute God-send!!!

For example:  I simply plugged in the exact information you gave me just like it's typed and selected "solve" and it asks what method to use and I just piced the substitution method just for the heck of it.  

What ever method used......   it shows you the work and gives you the answer.

So, it gave me the following answer, showing me the work, as well:  
 

x= 1/3
y= 1/2

Hope this site helps you guys as much as it has me!  LOL!