The order of the matrix having x rows and y columns is denoted by:

1. x + y

2. x - y

3. x × y

4. none of these

The total number of elements in an m × n matrix is:

1. m + n

2. mⁿ

3. mn

4. 2^{m + n}

The matrix, A = $\begin{bmatrix} 4 & 0 & 0 \ 0 & 3 & 0 \ 0 & 0 & -7 \end{bmatrix}$ is a:

1. Rectangular matrix

2. Column matrix

3. Diagonal matrix

4. Identity matrix

A matrix of order of 3 × 1 whose elements a_ij are given by a_ij = (2i + j), is :

1. $\begin{bmatrix} 3 & 5 & 7 \end{bmatrix}$

2. $\begin{bmatrix} 3 \ 5 \ 7 \end{bmatrix}$

3. $\begin{bmatrix} 2 & 4 & 6 \end{bmatrix}$

4. $\begin{bmatrix} 2 \ 4 \ 6 \end{bmatrix}$