Solving system of simultaneous linear equations by Cramer's rule

Solving system of simulateous linear equations 

Consider system of simulateous linear equations in in x ,y ,z 

\[a_1x+b_1y+c_1z=d_1\]

\[a_2x+b_2y+c_2z=d_2\]

\[a_3x+b_3y+c_3z=d_3\]

Matrix A can be defined as \[ \begin{bmatrix}a_1&b_1&c_1\\a_2&b_2&c_2\\a_3&b_3&c_3\end{bmatrix}\]

and B=\[\begin{bmatrix}d_1\\d_2\\d_3\end{bmatrix}\]

Then solution of system of equation can be written as 

AX=B

pre multipling both sides by \[A^{-1}\]

We get  \[A^{-1}AX=A^{-1}B\]

Which is equal to \[X=A^{-1}B\]  since \[A^{-1}A\] is an identity matrix.

 

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