__4.4 Multiplication of a Matrix by a Number__When matrix is multiplied by a number, every element in the matrix is multiplied by the number.

**Example:**

Given that
$A=\left(\begin{array}{cc}-2& 4\\ 5& -6\end{array}\right)$
, find each of the following.

$\begin{array}{l}\text{(a)}3A=3\left(\begin{array}{cc}-2& 4\\ 5& -6\end{array}\right)\\ =\left(\begin{array}{cc}3\times (-2)& 3\times 4\\ 3\times 5& 3\times (-6)\end{array}\right)\\ =\left(\begin{array}{cc}-6& 12\\ 15& -18\end{array}\right)\end{array}$
**(a)***3A***(b)***-2A*

*Solution:*$\begin{array}{l}\text{(b)}-2A=-2\left(\begin{array}{cc}-2& 4\\ 5& -6\end{array}\right)\\ =\left(\begin{array}{cc}-2\times (-2)& -2\times 4\\ -2\times 5& -2\times (-6)\end{array}\right)\\ =\left(\begin{array}{cc}4& -8\\ -10& 12\end{array}\right)\end{array}$

Hi, For example (b) -2A. There is a mistake where -2 x -2 should be 4 not -4. Please recitfy.

Dear Gurdit Singh,

thanks for pointing out our mistake, correction had been made accordingly.