Question:
$3 x-y+2 z=3$
$2 x+y+3 z=5$
$x-2 y-z=1$
Solution:
Given: $3 x-y+2 z=3$
$2 x+y+3 z=5$
$x-2 y-z=1$
$D=\left|\begin{array}{ccc}3 & -1 & 2 \\ 2 & 1 & 3 \\ 1 & -2 & -1\end{array}\right|$
$=3(-1+6)+1(-2-3)+2(-4-1)$
$=0$
$D_{1=}\left|\begin{array}{ccc}3 & -1 & 2 \\ 5 & 1 & 3 \\ 1 & -2 & -1\end{array}\right|$
$=3(-1+6)+1(-5-3)+2(-10-1)$
$=-15$
$D_{2}=\left|\begin{array}{ccc}3 & 3 & 2 \\ 2 & 5 & 3 \\ 1 & 1 & -1\end{array}\right|$
$=3(-5-3)-3(-2-3)+2(2-5)$
$=-15$
$D_{3}=\left|\begin{array}{ccc}3 & -1 & 3 \\ 2 & 1 & 5 \\ 1 & -2 & 1\end{array}\right|$
$=3(1+10)+1(2-5)+3(-4-1)$
$=-15$
Here, $D$ is zero, but $D_{1}, D_{2}$ and $D_{3}$ are non-zero. Thus, the system of linear equations is inconsistent.