Question

For what value of $x$, matrix $\left[\begin{array}{cc}6-x& 4\\ 3-x& 1\end{array}\right]$ is a singular matrix?

• A. $1$
• B. $2$
• C. $-1$
• D. $-2$

Answer 1

Answer: (B)

Matrix $A$ is singular, when $|A|=0$
$\left|\begin{array}{cc}6-x& 4\\ 3-x& 1\end{array}\right|=0$
$\Rightarrow 6-x-12+4x=0\Rightarrow 3x=6\Rightarrow x=2$