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solve the matrix: +7 +19 +31 +17 +21 +35

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lienetom | Student | eNoter

Posted February 7, 2012 at 5:10 PM via web

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solve the matrix:

+7 +19 +31

+17 +21 +35

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nathanshields | High School Teacher | (Level 1) Associate Educator

Posted February 7, 2012 at 6:14 PM (Answer #1)

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`[[7,19,31],[17,21,35]]`

The general way is to get a 1 in the top left (by dividing by 7):

`[[1, 19/7, 31/7],[17,21,35]]`

Now subtract seventeen times the top row from the bottom row: R2-17*R1 --> R2

`[[1,19/7,31/7],[0,-176/7 ,-282/7]]`

Now we turn Row 2 Column 2 into a "1" by multiplying by -7/176

`[[1, 19/7,31/7],[0,1,141/88]]`

Finish up by turning the 19/7 into a zero by: R1 - 19/7*R2 --> R1

`[[1, 0, 7/88],[0,1,141/88]]`

Cha-ching! Solved it.

 

 

 

 

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