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Homework Help: Cramer's Rule to solve for y

  1. Oct 20, 2011 #1
    1. The problem statement, all variables and given/known data

    Use Cramer's rule to solve for y (only). Call the 3x3 determinant D:

    (a) ax+by = 1
    cx+dy=0

    (b) ax+by+cz=1
    dx+ey+fz=0
    gx+hy+iz=0

    2. Relevant equations

    Cramer's Rule: x=A-1*b



    3. The attempt at a solution

    (a) So far I have,

    y= [det [a 1; c 0] / det [a b; c d]} = (0-c)/(ad-bc)=-c/(ad-bc)

    I don't know how to proceed...

    Same with part (b),

    y= [det[a 1 c; d 0 f; g o i]/det[a b c; d e f; g h i]] = (fg-di)/(aei+bfg+cdh-ceg-afh-ibd)

    Is there a way to simplify this?
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Oct 20, 2011 #2

    vela

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    You're done.
     
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