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Math Help - What makes this matrix true?

  1. #1
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    What makes this matrix true?

    what makes this matrix true?

    <br />
(\begin{array}{|ccc|}x&2&-1\\0&y&w\end{array}<br />
+ \begin{array}{|ccc|}0&1&2\\0&0&2\end{array})<br />
* \begin{array}{|ccc|}1&1\\3&z\\4&2\end{array}<br />
= \begin{array}{|ccc|}12&4\\2&2\end{array}<br />

    please help///
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  2. #2
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    Perform the operations as the problem suggests.

    1. add the matrices inside the brackets.
    2. multiply the result with the remaining LHS matrix.

    Show your work to there, i will then help further.
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  3. #3
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    Quote Originally Posted by pickslides View Post
    Perform the operations as the problem suggests.

    1. add the matrices inside the brackets.
    2. multiply the result with the remaining LHS matrix.

    Show your work to there, i will then help further.

    \begin{array}{|ccc|}x+0&2+1&-1+2\\0+0&y+0&w+2\end{array}<br />
=<br />
 \begin{array}{|ccc|}x&3&1\\0&y&w+2\end{array}<br />


    x,3,1
    0,y,w+2
    *
    1,1
    3,z
    4,2
    =
    x,9,1
    0,2y,,2w,4


    This is what i got....
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  4. #4
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    Quote Originally Posted by Anemori View Post


    x,3,1
    0,y,w+2
    *
    1,1
    3,z
    4,2
    =
    x,9,1
    0,2y,,2w,4

    I get

    \left(\begin{array}{ccc}x&3&1\\0&y&w+2\end{array}\  right) <br />
\times \left(\begin{array}{ccc}1&1\\3&z\\4&2\end{array}\r  ight)<br />
= \left(\begin{array}{cc}x+9+4&x+3z+2\\3y+4(w+2)&yz+  2(w+2)\end{array}\right)

    Now solve

     <br />
\left(\begin{array}{cc}x+9+4&x+3z+2\\3y+4(w+2)&yz+  2(w+2)\end{array}\right) = \left(\begin{array}{cc}12&4\\2&2\end{array}\right)<br />

    Might need to do some expanding on the LHS first!
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  5. #5
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    Quote Originally Posted by pickslides View Post
    I get

    \left(\begin{array}{ccc}x&3&1\\0&y&w+2\end{array}\  right) <br />
\times \left(\begin{array}{ccc}1&1\\3&z\\4&2\end{array}\r  ight)<br />
= \left(\begin{array}{cc}x+9+4&x+3z+2\\3y+4(w+2)&yz+  2(w+2)\end{array}\right)

    Now solve

     <br />
\left(\begin{array}{cc}x+9+4&x+3z+2\\3y+4(w+2)&yz+  2(w+2)\end{array}\right) = \left(\begin{array}{cc}12&4\\2&2\end{array}\right)<br />

    Might need to do some expanding on the LHS first!

    What do you mean expand? How do you do that?
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  6. #6
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    Quote Originally Posted by Anemori View Post
    What do you mean expand? How do you do that?
    I mean the bottom terms in the LHS matrix.

    I.e. 3y+4(w+2) = 3y+4w+8

    You then need to make 4 equations and solve them simultaneously.

    Equate the term in each corresponding postition from each matrix.

    Here's the first.

    x+9+4= 12
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  7. #7
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    Thanks .. i got it...
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