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If $$\left|\begin{array}{cc} {x} & {2} \\ {18} & {x} \end{array}\right|=\left|\begin{array}{cc} {6} & {2} \\ {18} & {6} \end{array}\right|$$ , then x is equal to
• $$\pm$$6
• 0
• -6
• 6
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## QuestionMathsClass 12

If $$\left|\begin{array}{cc} {x} & {2} \\ {18} & {x} \end{array}\right|=\left|\begin{array}{cc} {6} & {2} \\ {18} & {6} \end{array}\right|$$ , then x is equal to
• $$\pm$$6
• 0
• -6
• 6

We have $$\left|\begin{array}{ll} {x} & {2} \\ {18} & {x} \end{array}\right|=\left|\begin{array}{ll} {6} & {2} \\ {18} & {6} \end{array}\right|$$
We know that determinant of A is calculated as $$|A|=\left|\begin{array}{ll} {a} & {b} \\ {c} & {d} \end{array}\right|$$ = ad - bc
$$\Rightarrow$$ x(x) – 2(18) = 6(6) – 2(18)
$$\Rightarrow$$ x2 - 36 = 36 – 36
$$\Rightarrow$$ x2 =36 – 36 + 36
$$\Rightarrow$$ x2 = 36
$$\Rightarrow$$ x = $$\pm$$6
Therefore the choice is: A
4.6
4.6
Correct2
Incorrect0
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