The number of solutions of the system of equations $2x + y – z = 7,\,\,x – 3y + 2z = 1,\,x + 4y – 3z = 5$ is

An ordered pair $(\alpha , \beta )$ for which the system of linear equations

$\left( {1 + \alpha } \right)x + \beta y + z = 2$ ; $\alpha x + \left( {1 + \beta } \right)y + z = 3$ ; $\alpha x  + \beta y + 2z = 2$ has a unique solution, is

The roots of the equation $\left| {\,\begin{array}{*{20}{c}}1&4&{20}\\1&{ – 2}&5\\1&{2x}&{5{x^2}}\end{array}\,} \right| = 0$ are

If $\left| {\,\begin{array}{*{20}{c}}{3x – 8}&3&3\\3&{3x – 8}&3\\3&3&{3x – 8}\end{array}\,} \right| = 0,$ then the values of $x$ are

If $a \ne p,b \ne q,c \ne r$ and $\left| {\,\begin{array}{*{20}{c}}p&b&c\\{p + a}&{q + b}&{2c}\\a&b&r\end{array}\,} \right|$ =$ 0$, then $\frac{p}{{p – a}} + \frac{q}{{q – b}} + \frac{r}{{r – c}} = $