Homework Help: Finding x and y in matrix

Can someone tell me what i'm doing wrong. the answer for x is supposed to be -3/7 and y is supposed to be 5/7 but i have 5/7 and -23/7.

[tex]


\begin{bmatrix}
1 & -2 \\
3 & 1
\end{bmatrix}
\begin{bmatrix}
1 & 0 \\
0 & 1
\end{bmatrix}



[/tex]
new r1= r1-(r2 x -2)
[tex]


\begin{bmatrix}
7 & 0 \\
3 & 1
\end{bmatrix}
\begin{bmatrix}
1 & -2 \\
0 & 1
\end{bmatrix}



[/tex]
new r1=r1/7
[tex]


\begin{bmatrix}
1 & 0 \\
3 & 1
\end{bmatrix}
\begin{bmatrix}
1/7 & -2/7 \\
0 & 1
\end{bmatrix}



[/tex]
new r2 = r2-(r1 x 3)
[tex]


\begin{bmatrix}
1 & 0 \\
0 & 1
\end{bmatrix}
\begin{bmatrix}
1/7 & -2/7 \\
-3/7 & 13/7
\end{bmatrix}



[/tex]

[tex]

b=\begin{bmatrix}
1 \\
-2
\end{bmatrix}
[/tex]
so
[tex]

\begin{bmatrix}
1/7 & -2/7 \\
-3/7 & 13/7
\end{bmatrix}
\begin{bmatrix}
1 \\
-2
\end{bmatrix}



[/tex]

[tex]
4/7 + 1/7 = 5/7
[/tex]
[tex]
-26/7 + 3/7 = -23/7
[/tex]

 

yes its negative 5/7 actually.