# Augmented matrices

1. May 7, 2008

### Ry122

How is this an augmented matrix?
Shouldn't 0 and 7 be 3 and 1 and alpha be -2?
http://users.on.net/~rohanlal/Untitled-1.jpg [Broken]

Last edited by a moderator: May 3, 2017
2. May 7, 2008

### HallsofIvy

Staff Emeritus
The problem says associated augmented matrix.

Yes, construct the augmented matrix just as you say, then row-reduce to what they show. What is alpha?

3. May 7, 2008

### Ry122

What is the matrix that is shown? Is it the inverse matrix?

http://en.wikipedia.org/wiki/Alpha_(letter [Broken])

Last edited by a moderator: May 3, 2017
4. May 7, 2008

### rootX

:rofl:

I think he meant what is the alpha value when you transform your original augmented matrix to the final one (just do some row ops)

Last edited by a moderator: May 3, 2017
5. May 7, 2008

### Defennder

No, it's not the inverse matrix. That matrix is obtained when you express the 2 linear equations in the form of a matrix:

$$\left(\begin{array}{ccc}1&-2&1\\3&1&-2\end{array}\right)$$

EDIT: I have no idea how to draw the vertical line in the matrix to represent an augmented matrix.

From here you just use row operations to get the matrix in the form given by the question. Alpha is then the value of whatever you have in entry row 2 column 3 of your reduced-row matrix