(a) If $\text{P} = \begin{bmatrix} 1 & -1 & 0 \\ 2 & 3 & 4 \\ 0 & 1 & 2 \end{bmatrix}$ and $\text{Q} = \begin{bmatrix} 2 & 2 & -4 \\ -4 & 2 & -4 \\ 2 & -1 & 5 \end{bmatrix}$, find $(\text{QP})$ and hence solve the following system of equations using matrices :\n$x - y = 3$, $2x + 3y + 4z = 17$, $y + 2z = 7$\nOR