# Given the matrices A=[(5,7),(-1,6), (3,-9)], B=[(8,3), (5,1), (4,4)], C=[(0,4),(-2,5), (7,-1)], D[(6,2), (9,0), (-3,0)], how do you find 4C?

Aug 4, 2017

$4 C = \left[\begin{matrix}0 & 16 \\ - 8 & 20 \\ 28 & - 4\end{matrix}\right]$

#### Explanation:

To find $4 C$, multiply the $4$ throughout the entire matrix $C$.

$\textcolor{red}{4} \left[\begin{matrix}0 & 4 \\ - 2 & 5 \\ 7 & - 1\end{matrix}\right]$

=$\left[\begin{matrix}\textcolor{red}{4} \cdot 0 & \textcolor{red}{4} \cdot 4 \\ \textcolor{red}{4} \cdot - 2 & \textcolor{red}{4} \cdot 5 \\ \textcolor{red}{4} \cdot 7 & \textcolor{red}{4} \cdot - 1\end{matrix}\right]$

=$\left[\begin{matrix}0 & 16 \\ - 8 & 20 \\ 28 & - 4\end{matrix}\right]$

Aug 4, 2017

$\left(\begin{matrix}0 & 16 \\ - 8 & 20 \\ 28 & - 4\end{matrix}\right)$

#### Explanation:

$\text{multiply each of the elements of C by 4}$

$\Rightarrow 4 C = \textcolor{red}{4} \left(\begin{matrix}0 & 4 \\ - 2 & 5 \\ 7 & - 1\end{matrix}\right)$

$\textcolor{w h i t e}{\Rightarrow 4 C} = \left(\begin{matrix}\textcolor{red}{4} \times 0 & \textcolor{red}{4} \times 4 \\ \textcolor{red}{4} \times - 2 & \textcolor{red}{4} \times 5 \\ \textcolor{red}{4} \times 7 & \textcolor{red}{4} \times - 1\end{matrix}\right)$

$\textcolor{w h i t e}{\Rightarrow 4 C} = \left(\begin{matrix}0 & 16 \\ - 8 & 20 \\ 28 & - 4\end{matrix}\right)$