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Math Help - Solving Simultaneous Equations Using Matrices

  1. #1
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    Solving Simultaneous Equations Using Matrices

    I've tried a problem for a very long time but I can't seem to get it right (my answer is different from the one in my textbook).

    Could you please tell me where I went wrong?

    Thank you!
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  2. #2
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    Your inverse matrix is incorrect. You have correctly calculated the determinant but you also need to swap two entries and negate the other two.


     <br />
\frac{-1}{106}\left[\begin{array} {cc} -10&-8 \\ -7&5 \end{array}\right]<br />
\left[\begin{array} {cc} 5&8 \\ 7&-10 \end{array}\right]=<br />
\left[\begin{array} {cc} 1&0 \\ 0&1 \end{array}\right]<br />
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  3. #3
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    Oh wait I'm sorry I did do the swapping and negating, I just forgot to include it in the image.

    Could you show me how to solve it? Cause I still keep getting a wrong answer.
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