Elementary Row Operation - Matrix

[bellerum23]

Use an elementary row operation to find the missing number in the second matrix.

| 1 2 -1 |
| 2 -2 3 | ,

| 1 2 -1 |
|-1 -8 x |

The missing x number/answer is 6, but how do I get to that answer.

[stapel_eliz]

Use an elementary row operation to find the missing number in the second matrix.

| 1 2 -1 |
| 2 -2 3 | ,

| 1 2 -1 |
|-1 -8 x |

To enforce spacing-dependent formatting, you'll need to use "code" tags, such as:

Code: Select all

| 1  2 -1|
|-1 -8  x|

Note: Given only the posted information, there is no way to tell what might be the value of "x" in the second matrix. What is the point of the first matrix, by the way? Is it somehow related? Thank you.