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Math Help - Elementary row operations

  1. #1
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    Elementary row operations

    Find solutions using elementary row operations

    x+2y+z=0
    2x+5y+2x=0
    x+4y+7z=0
    x+3y+3z=0

    I subtracted 2 times the 1st equation from the 2nd to get y=0 and I subtracted the 4th eq from equation 3 to get y+4z=0, so z also equals 0. X would also equal 0, but did I do enough steps to qualify for elementray row operations? I don't want to lose points because I missed steps.
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  2. #2
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    Quote Originally Posted by antman View Post
    Find solutions using elementary row operations

    x+2y+z=0
    2x+5y+2x=0
    x+4y+7z=0
    x+3y+3z=0

    I subtracted 2 times the 1st equation from the 2nd to get y=0 and I subtracted the 4th eq from equation 3 to get y+4z=0, so z also equals 0. X would also equal 0, but did I do enough steps to qualify for elementray row operations? I don't want to lose points because I missed steps.
    Yes that's fine.
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  3. #3
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    I'll assume Prove It followed your work correctly. I just wanted to see if you realize that elementary row operations refer to a matrix. The coefficients of all the variables are taken in order and the last entry is the constant, which are all 0 here. So if your first equation is like ax+by+cz=d, then the matrix row would be [a b c d]. You are trying to get them in the form of two out of three of a,b and c being zero and the other one being 1 and then d can be whatever. So if the first row is "solved" it should be in the form of [1 0 0 x_a], where x_a is the value of x. You are doing this essentially but I didn't know if you really got the connection to a matrix. I guess this also depends on how your teacher is teaching this.
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