How do i solve equations by substitution?

Just doing one! Here's my problem: x-y-11 x-3y=1

So when you subsitute everything it should look like this: 1y-11-3y=1 (There needs to be a one in front of the y because it's just always been there. they don't always put it in the eqation.) You need to + the 11 and you have to do that to each side. So ... 1y-11-3=1

+11 + 11

Now it should look like this: 1y-3y=12

Combine the 1y and - 3y to get - 4y=12 Last step is divide - 4y and 12 by 4. Answer is y=3