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Homework Help: Scaling a row scales the determinant

  1. Nov 17, 2012 #1
    1. The problem statement, all variables and given/known data
    http://puu.sh/1rcsO [Broken]

    I got the first one from a simple scaling, but I can not figure out the second one.

    2. Relevant equations
    Det(cA) = cDet(A)
    Scaling a row scales the determinant
    Adding rows/columns to each other does not affect the determinant
    Det(AT) = Det A

    3. The attempt at a solution
    So, shouldn't I be able to scale http://puu.sh/1rcyZ [Broken] by -2, and just add row 2 and row 3 by multiples of row 1 ? I actually don't even think this is even close to right because the column 1 and 3 won't resemble each other at all once the row operations are done...
    Last edited by a moderator: May 6, 2017
  2. jcsd
  3. Nov 17, 2012 #2


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    Science Advisor
    Homework Helper

    Hi Lifprasir! :smile:

    Hint: what are the gaps between 1,2,3?

    what are the gaps between -2,-8,-14? :wink:
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