Task Sets: Multiply matrices by scalars - Common Core Math - HS Number and Quantity

1.

Compute $-2 \begin{bmatrix} 1 & 3 \\ -4 & 0 \end{bmatrix}$ . Which matrix is the result?

A.

$\begin{bmatrix} -2 & -6 \\ 8 & 0 \end{bmatrix}$

B.

$\begin{bmatrix} -2 & -6 \\ -8 & 0 \end{bmatrix}$

C.

$\begin{bmatrix} -1 & -3 \\ 4 & 0 \end{bmatrix}$

D.

$\begin{bmatrix} 2 & 6 \\ -8 & 0 \end{bmatrix}$

2.

Compute $4 \begin{bmatrix} 3 & -1 & 0 \\ 2 & 5 & -3 \end{bmatrix}$ . What is the entry in row 2, column 3?

3.

For $A = \begin{bmatrix} 5 & 2 \\ -1 & 3 \end{bmatrix}$ , find the $(1,1)$ entry of $(-1)A$ (i.e., $-A$ ).

4.

Matrix $B$ has dimensions $2 \times 4$ . Which statement about $cB$ (for any nonzero real $c$ ) is always true?

A.

The dimensions of $cB$ depend on whether $c$ is positive or negative.

B.

The dimensions of $cB$ are $2 \times 4$ .

C.

The dimensions of $cB$ are the same as the dimensions of $c$ , which is $1 \times 1$ .

D.

The dimensions of $cB$ are $2c \times 4c$ .

Exercises: Multiply Matrices by Scalars