Write a system that matches up with the information:
You can solve this with elimination. In this case, add them together to get rid of y.
Plug in to solve for y.
Let the numbers be
If we add the two equations we get:
Now, we can plug this into any of the equations to solve for
9 and 7
Well, what you have is, 2 equations in 2 unknowns. Which is enough to find a solution. There are a couple of ways to proceed, which no doubt you'll learn. For this example, probably the simplest is substitution.
Your 2 equations are:
From the second equation, we can say that:
...and now we substitute this value of a in the first equation:
...and now we can plug this back into the second equation, and solve for a: