The number of values of $\alpha$ for which the system of equations: $x+y+z=\alpha$ ; $\alpha x+2 \alpha y+3 z=-1$ ; $x+3 \alpha y+5 z=4$ is inconsistent, is
$0$
$1$
$2$
$3$
If $\left| {{\kern 1pt} \begin{array}{*{20}{c}}1&2&3\\2&x&3\\3&4&5\end{array}\,} \right| = 0,$ then $x =$
The system of equations $\begin{array}{l}\alpha x + y + z = \alpha - 1\\x + \alpha y + z = \alpha - 1\\x + y + \alpha z = \alpha - 1\end{array}$ has no solution, if $\alpha $ is
The following system of linear equations $7 x+6 y-2 z=0$ ; $3 x+4 y+2 z=0$ ; ${x}-2{y}-6{z}=0,$ has
If $A \ne O$ and $B \ne O$ are $ n × n$ matrix such that $AB = O,$ then
If the system of linear equations $x+y+3 z=0$
$x+3 y+k^{2} z=0$
$3 x+y+3 z=0$
has a non-zero solution $(x, y, z)$ for some $k \in R ,$ then $x +\left(\frac{ y }{ z }\right)$ is equal to