Find x and y if [ cc 4 & 3 x x & -2 ] [ l 5 1 ]= [ l y 8 ] - Vidyadip

Question

Find $x$ and $y$ if $\left[\begin{array}{cc}4 & 3 x \\ x & -2\end{array}\right]\left[\begin{array}{l}5 \\ 1\end{array}\right]=\left[\begin{array}{l}y \\ 8\end{array}\right]$

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Answer

$\begin{array}{l}{\left[\begin{array}{cc}4 & 3 x \\ x & -2\end{array}\right]\left[\begin{array}{l}5 \\ 1\end{array}\right]=\left[\begin{array}{l}y \\ 8\end{array}\right]} \end{array} $
$ {\left[\begin{array}{c}20+3 x \\ 5 x-2\end{array}\right]=\left[\begin{array}{l}y \\ 8\end{array}\right]}$
Comparing the corresponding elements we get
$5 x-2=8 $
$\Rightarrow x=2$
$20 + 3x = y $
$\Rightarrow y = 20 + 6 $
$= 26$

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