SOLUTION: I need help solving the system by using the Gauss-Jordan elimination method. w/out a calculator. 2x-1y+2z=9 1x+3+0=5 3x+0+1z=9 thank you !!!

Algebra ->  Matrices-and-determiminant -> SOLUTION: I need help solving the system by using the Gauss-Jordan elimination method. w/out a calculator. 2x-1y+2z=9 1x+3+0=5 3x+0+1z=9 thank you !!!      Log On


   

Question 910663: I need help solving the system by using the Gauss-Jordan elimination method. w/out a calculator.
2x-1y+2z=9
1x+3+0=5
3x+0+1z=9
thank you !!!
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
The starting matrix:

%28matrix%283%2C4%2C%0D%0A2%2C-1%2C2%2C9%2C%0D%0A1%2C3%2C0%2C5%2C%0D%0A3%2C0%2C1%2C9%29%29

I went through these steps, which I am indicating in abbreviated form:

Switch R1 and R2;
R2-2R1, R3-3R1;
-1*R2 and -1*R3;
(1/7)R2 and (1/9)R3;
R3-R1;
computation for R3;
21*R3
(3/11)R3;
R2=R2+(2/7)R3;
R1=R1-3R2.

Final matrix became