Question:
If $\left[\begin{array}{cc}2 x+y & 3 y \\ 0 & 4\end{array}\right]=\left[\begin{array}{ll}6 & 0 \\ 6 & 4\end{array}\right]$, then find $x$
Solution:
The corresponding elements of two equal matrices are equal.
Given : $\left[\begin{array}{cc}2 x+y & 3 y \\ 0 & 4\end{array}\right]=\left[\begin{array}{ll}6 & 0 \\ 6 & 4\end{array}\right]$
$2 x+y=6 \quad \ldots(1)$
$3 y=0$
$\Rightarrow y=0$
Putting the value of $y$ in eq. (1)
$2 x+0=6$
$\Rightarrow 2 x=6$
$\Rightarrow x=\frac{6}{2}$
$\therefore x=3$