SOLUTION: I have done the first one, but I have a feeling it is incorrect. If by chance someone could help me out please!! :) Id really appreciate it!!! --Solve each system by elimination

Question 466739: I have done the first one, but I have a feeling it is incorrect. If by chance someone could help me out please!! :) Id really appreciate it!!!
--Solve each system by elimination--
a) x-y=3
x+3y=3
b) -x+3y=6
x-9y=9
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
a)
x-y=3
x+3y=3
---
Subtract and solve for "y":
4y = 0
y = 0
---
solve for "x":
x-y = 3
x-0=3
x = 3
=============================
b)
-x+3y=6
x-9y=9
---
Add and solve for "y":
-6y = 15
y = -5/2
---
Solve for "x":
-x + 3(-5/2) = 6
-x -(15/2) = 6
-x = 13.5
x = -13.5
===================
Cheers,
Stan H.
=======================

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