Steps:
So for this, we will be setting up a system of equations with the information we have:

Now we have our system of equations set up. Next, I will be using the substitution method to solve this system. So firstly, subtract y on both sides of the first equation:

Now, substitute x for (13 - y) in the second equation and solve for y as such:

Now that we have the value of y, substitute it into either equation to solve for x:

Answer:
In short, the first number (x) is 8 and the second number (y) is 5.