Basics of Matrices

If $p+q+r=a+b+c=0$, then the determinant $\left|\begin{array}{lll}pa& qb& rc\\ qc& ra& pb\\ rb& pc& qa\end{array}\right|$ equals

Let $A+2B=\left[\begin{array}{ccc}1& 2& 0\\ 6& -3& 3\\ -5& 3& 1\end{array}\right]$ and $2A-B=\left[\begin{array}{ccc}2& -1& 5\\ 2& -1& 6\\ 0& 1& 2\end{array}\right].$ If $Tr\left(A\right)$ denotes the sum of all diagonal elements of the matrix $A,$ then $Tr\left(A\right)-Tr\left(B\right)$ has value equal to

A matrix $A=\left[a_{ij}\right]$ of order $2\times 3$ whose elements are such that $a_{ij}=i+j$ is

The upper triangular matrix of the matrix $\left[\begin{array}{ccc}1& -1& 2\\ 2& 1& 3\\ 3& 2& 4\end{array}\right]$ is