Substitution? Easy as pie! Think of it this way, when you substitute something, you're replacing it with something else, right? That's what substitution in math is about too. You replace a letter you don't know with something you do know, so you can make the problem easy to solve.
Step 1: Write out both equations.
Step 2: Make one of them equal to y, by moving things numbers around (use the opposites to move them from one side of the equation to the other.)
Step 3: Go to the second equation and plug in the part of the first equation that is after the equal sign.
Step 4: Solve the second equation by adding or subtracting like terms.
Step 5: Plug in that answer into the first equation and solve for the second unknown number (variable).
That's all there is to it...well, besides checking to make sure they both equal the numbers on the other side of the equations!
Let's try your example:
-x from both sides of the equation.
You are now left with -y=2-x
Divide by -1 to get y alone.
Do the same thing to the other side. Divide by -1
When you divide by a negative 1, all the signs change to the opposite signs.
So, y = -2+x
plug that into the second equation. Wherever you see y in the second equation, replace it with the -2+x.
Then, solve the second equation.
Use distribution to solve for the parenthesis part and you will have 4x+6-3x=11
Add like terms: 4x-3x=1x or just x
You will now be left with: x+6=11
Subtract 6 from both sides.
Plug that answer back into the first original equation and solve for y.
subtract 5 from both sides: 5-5-y=2-5
divide by -1 and you will have y = 3
Now, you just check to make sure it all works out, by plugging both answers back into both equations and seeing if they equal the totals already in the original equations.
For instance: x-y=2
Does it check? Yes, it does!
Do the same with the other one and presto...you're a math whiz! ;)