- #1

- 565

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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]

[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]

Last edited: