How should I start this system-solving problem?

[taronej]

I'm in the military and studying for an officer test. I haven't done any math in while. I just need some help how to get started on these two particulary problems? Any help at all would be great!

Solve the system of equations.

1) 3x - 2y = .1
. ..4x - 5y = -8

2) 1x - 2y + 1z = .5
. ..2x + .y - . .z = -1
. ..3x - 1y + 2z = .8

 

[pka]

2)
\(\displaystyle \begin{array}{l}
\left\{ \begin{array}{l}
x - 2y + z = 5 \\
2x + y - z = - 1 \\
\end{array} \right.\quad \Rightarrow \quad 3x - y = 4 \\
\left\{ \begin{array}{l}
2x + y - z = - 1 \\
3x - y + 2z = 8 \\
\end{array} \right.\quad \Rightarrow \quad \left\{ \begin{array}{l}
4x + 2y - 2z = - 2 \\
3x - y + 2z = 8 \\
\end{array} \right.\quad \Rightarrow \quad 7x + y = 6 \\
\left\{ \begin{array}{l}
3x - y = 4 \\
7x + y = 6 \\
\end{array} \right.\quad \Rightarrow \quad 10x = 10\quad \Rightarrow \quad x = 1 \\
x = 1\quad \Rightarrow \quad y = - 1\quad \Rightarrow \quad z = 2 \\
\end{array}\)

 

[Denis]

do a http://www.google.com search on "solving equation systems"; lotsa sites, like:

http://tutorial.math.lamar.edu/AllBrows ... ystems.asp