Thanks,
That did help a lot. I tried doing one on my own right after, but am a little stuck.
x-2y=4
2x-4y=5
I did:
2y=4+x
2x-4(4+x)=5
2x-16+4x=5 ----> 6x = ?
Edit: Your method is littered with small errors: did you check it?
$\displaystyle 1) x-2y=4$
$\displaystyle 2) 2x-4y=5$
From $\displaystyle 1)$, $\displaystyle x=4+2y$
Substituting this into $\displaystyle 2)$:
$\displaystyle 2(4+2y)-4y=5$
Try to solve this, and you will realize that $\displaystyle 8\neq{5}$ as the original equations suggest. Do you have a typo?