SOLUTION: Solve the following system of equations for the uknown variables. 3x+3y=3 -3x-2z=-11 Y+z=-1

Algebra ->  Systems-of-equations -> SOLUTION: Solve the following system of equations for the uknown variables. 3x+3y=3 -3x-2z=-11 Y+z=-1      Log On


   

Question 768657: Solve the following system of equations for the uknown variables.
3x+3y=3
-3x-2z=-11
Y+z=-1
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
3x + 3y = 3
-3x- 2z =-11
Y + z = -1
:
Rewrite this to
3x + 3y + 0z = 3
-3x+ 0y - 2z =-11
0x + Y + z = -1
:
Add the first two equations
3x + 3y + 0z = 3
-3x+ 0y - 2z =-11
------------------ eliminates x
3y - 2z = -8
:
Multiply the 3rd equation by 2, add to the above equation
2y + 2z = -2
3y - 2z = -8
---------------
5y = -10
y = -10/5
y = -2
:
Find z using the 3rd equation
-2 + z = -1
z = -1 + 2
z = 1
;
You can find x using the 1st equation (replace y with -2)