Hi Justice,
Three equations three unknowns! Nice! The trick to preventing these from getting complicated is to start by eliminating a variable. To do this you add or subtract one equation (or multiple thereof) from another equation (or multiple thereof).
If you're confused that's ok, just bear with me for a second. You already know that you can add two things which equal each other to two other things which equal each other. For example if m=5 and n=10 then m+n=5+10
So, back to your problem, what would happen if you added the first and second equation together? That's right, you'd get: 5x+2y=17
Fancy that, we got rid of the "z" which is good because we're down to just two variables. Unfortunately to solve for this we'd need another unique equation which only has "Xs" and "Ys" in it. We can get this by adding the 2nd equation you gave me to the third which results in: 3x+5y=14
This leaves us with two equations two unknowns which you should already know how to solve (since you've moved on to working on 3 equations three unknowns). Once you get the values for both X and Y, you plug them into any one of the initial 3 equations and get the value for z.
WIN!
PS: if you actually do not know how to solve for two equations two unknowns then make a comment here and I will come back and help you with that.
