Solving a Matrice Equation: AX=B

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SUMMARY

The discussion focuses on solving the matrix equation \(AX=B\) where \(A\) is a 3x3 matrix, \(X\) is a 3x2 matrix, and \(B\) is a 3x2 matrix. The participant initially believes there is no solution due to the dimensions of the matrices, but another participant clarifies that \(A\) is invertible, allowing the equation to be solved as \(X=A^{-1}B\). This confirms that the multiplication of \(A^{-1}\) and \(B\) is valid and provides a pathway to find \(X\).

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Petrus
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Matrice equation

Hello MHB,
I am suposed to solve this matrice equation $$AX=B$$
$$A=
\left| {\begin{array}{cc} 1 & 2 & 1\\ 1 & 3 & 2\\ 1 & 6 & 6 \end{array} } \right|$$
$$X=
\left| {\begin{array}{cc} a & b \\ c & d \\ e & f \end{array} } \right|$$
$$B=
\left| {\begin{array}{cc} 1 & 10 \\ 2 & 40 \\ 3 & 60 \end{array} } \right|$$

Well I don't need to try do something I can se there will be no solution cause I will not be able to multiplication $$A^{-1}*B$$ cause there is not same row in A as columne in B so there will be no solution? I am correct?

Regards,
$$|\pi\rangle$$
 
Last edited:
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Re: Matrice equation

No problem with orders, they fit perfectly. Besides, $A$ is invertible so, $$AX=B\Leftrightarrow A^{-1}(AX)=A^{-1}B\Leftrightarrow (AA^{-1})X=A^{-1}B\Leftrightarrow IX=A^{-1}B\Leftrightarrow X=A^{-1}B$$ Now, $X=A^{-1}B=\ldots$
 
Re: Matrice equation

Fernando Revilla said:
No problem with orders, they fit perfectly. Besides, $A$ is invertible so, $$AX=B\Leftrightarrow A^{-1}(AX)=A^{-1}B\Leftrightarrow (AA^{-1})X=A^{-1}B\Leftrightarrow IX=A^{-1}B\Leftrightarrow X=A^{-1}B$$ Now, $X=A^{-1}B=\ldots$
Hello Fernando Revilla,
Thanks, I see what I did misinterpret.

Regards,
$$|\pi\rangle$$
 

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