Consider system of equations  $ x + y -az = 1$  ;  $2x + ay + z = 1$   ; $ax + y -z = 2$

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

If $a, b, c$ are sides of a scalene triangle, then the value of $\left| \begin{array}{*{20}{c}}
a&b&c\\
b&c&a\\
c&a&b
\end{array} \right|$ is

For real numbers $\alpha$ and $\beta$, consider the following system of linear equations:

$x+y-z=2, x+2 y+\alpha z=1,2 x-y+z=\beta$. If the system has infinite solutions, then $\alpha+\beta$ is equal to $…..$

Let $[\lambda]$ be the greatest integer less than or equal to $\lambda$. The set of all values of $\lambda$ for which the system of linear equations $x+y+z=4,3 x+2 y+5 z=3$ $9 x+4 y+(28+[\lambda]) z=[\lambda]$ has a solution is: