Question

If $\begin{vmatrix}x&2\\\18&x\end{vmatrix}=\begin{vmatrix}6&2\\\18&6\end{vmatrix}$,then x is equal to

• A. 6
• B. ±6
• C. -6
• D. 0

Answer 1

Answer: (B)

±6

Answer 2

$\begin{vmatrix}x&2\\\18&x\end{vmatrix}=\begin{vmatrix}6&2\\\18&6\end{vmatrix}$
$\Rightarrow$ x2-36=36-36
$\Rightarrow$ x2-36=0
$\Rightarrow$ x2=36
$\Rightarrow$ x=±6

Hence, the correct answer is B.