Respuesta :

The first two rows of coefficients are identical, so by inspection, the determinant is 0.

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Answer:

The determinant of  coefficient  matrix of the given system is 0.

Step-by-step explanation:

Given system of equation

[tex]-x-y-z=-3[/tex]

[tex]-x-y-z=8[/tex]

[tex]3x+2y+z=0[/tex]

The coefficient matrix of the system

[tex]\left[\begin{array}{ccc}-1&-1&-1\\-1&-1&-1\\3&2&1\end{array}\right][/tex]

Let A=[tex]\left[\begin{array}{ccc}-1&-1&-1\\-1&-1&-1\\3&2&1\end{array}\right][/tex]

X=[tex]\left[\begin{array}{}x&y&z\end{array}\right][/tex]

B=[tex]\left[\begin{array}-3 &8&0\end{array}\right][/tex]

Therefore , we can AX=B

[tex]\left[\begin{array}{ccc}-1&-1&-1\\1&-1&-1\\3&2&1\end{array}\right][/tex][tex]\left[\begin{array}{}x&y&z \end{array}\right][/tex]=[tex]\left[\begin{array}{}-3&8&0\end{array}\right][/tex]

The determinant of  coefficient matrix of the given system is given by

[tex]\begin{vmatrix}-1&-1&-1\\-1&-1&-1\\3&2&1\end{vmatrix}[/tex]

By using determinant property : when two rowsor two columns are identical then the value of determinant is equal to zero .

[tex]\therefore \begin{vmatrix}A\end{vmatrix}=0[/tex]