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Assume A = [[5,-2],[-6,-7]] and b = [[1],[2]] Use A^-1 to solve Ax = b.    

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masterpiece11 | Student | (Level 1) Salutatorian

Posted April 13, 2013 at 10:27 PM via web

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Assume A = [[5,-2],[-6,-7]] and b = [[1],[2]]

Use A^-1 to solve Ax = b.

 

 

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pramodpandey | College Teacher | (Level 3) Valedictorian

Posted April 14, 2013 at 4:30 AM (Answer #1)

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`A=[[5,-2],[-6,-7]] ,b=[[1],[2]]`

`|A|=-35-12=-47`

`A^(-1)=(-1/47)[[-7,2],[6,5]]`

`AX=b`

`A^(-1)AX=A^(-1)b`

`X=A^(-1)b`

`=(-1/47)[[-7,2],[6,5]][[1],[2]]`

`X=(-1/47)[[-7+4],[6+10]]`

`X=[[3/47],[-16/47]]`

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