1. $\mathrm{L}=\left[\begin{array}{rrr} 2 & 1 & 3 \\ -1 & 3 & -1 \\ -1 & 2 & -5 \end{array}\right], \mathrm{M}=\left[\begin{array}{l} 6 \\ 1 \\ 1 \end{array}\right], \mathrm{N}=\left[\begin{array}{l} \mathrm{x} \\ \mathrm{y} \\ z \end{array}\right] \text { এবং } \mathrm{A}=\left|\begin{array}{lll} \mathrm{P}^{2} & \mathrm{a}^{2} & \mathrm{a}^{2} \\ \mathrm{~b}^{2} & \mathrm{Q}^{2} & \mathrm{~b}^{2} \\ \mathrm{c}^{2} & \mathrm{c}^{2} & \mathrm{R}^{2} \end{array}\right|$