SOLUTION: The firstt two rows of the following matrix are already in triangular form. Finish the job by performing Gaussian elimination on row 3. What are the contents of row 3 after you ha

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Question 627018: The firstt two rows of the following matrix are already in triangular form. Finish the job by performing Gaussian elimination on row 3. What are the contents of row 3 after you have done so?
[1 6 -2 0]
[0 -3 1 5]
[2 0 3 9]
1. 0 0 3 29
2. 0 0 1 9
3. 0 0 3 -11
4. 0 0 -5 -11
can you please help me figure this out and show how you did it. ty

Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
The firstt two rows of the following matrix are already in triangular form. Finish the job by performing Gaussian elimination on row 3. What are the contents of row 3 after you have done so?
[1 6 -2 0]
[0 -3 1 5]
[2 0 3 9]
-------------------
Subtract 2 times the 1st row from the 3rd row to get:
[1 6 -2 0]
[0 -3 1 5]
[0 -12 7 9]
---
Subtract 4 times the 2nd row from the 3rd row to get:
[1 6 -2 0]
[0 -3 1 5]
[0 0 3 -11]
------
Solution: [0 0 3 -11]
----
Cheers,
Stan H.
-----
1. 0 0 3 29
2. 0 0 1 9
3. 0 0 3 -11
4. 0 0 -5 -11

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