Using elimination means that you add an ENTIRE FUNCTION to another one, you do this by adding each individual term, to arrive at an equality of one term, then you use back-substitution to finish the problem:

You have:

and

Notice, you have a positive and a negative y, let's add these two together and see what we come up with:

Now we just add each set of terms, starting with the x's:

Next, the y's:

<--- Just got rid of the y's

Next, the constants:

Now, we construct a new equation:

Solve for x:

Now, we have to find a y:

All we do, is check the OTHER equation for validity:

That is true, so it works.