Question

If $\left[\begin{array}{cc}8& 4\\ x& 8\end{array}\right]=4\left[\begin{array}{cc}2& 1\\ 1& 2\end{array}\right],$ then the value of $x$ is

• A. $1$
• B. $2$
• C. $\frac{1}{4}$
• D. $4$

Answer 1

The correct option is D $4$

Since,

$\left[\begin{array}{cc}8& 4\\ x& 8\end{array}\right]=4\left[\begin{array}{cc}2& 1\\ 1& 2\end{array}\right]$

$\Rightarrow \left[\begin{array}{cc}8& 4\\ x& 8\end{array}\right]=\left[\begin{array}{cc}8& 4\\ 4& 8\end{array}\right]$

$\Rightarrow x=4$

Hence, the answer is $x=4.$