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-- Mathematics - Section A
Determinants
If \(x=\begin{bmatrix}1 & 2 & 3\\2 & 3 & 1\\3 & 1 & 2\end{bmatrix}\) then value of 9 - 2x is:
27
-36
45
-54
$|x|=1(6-1)-2(4-3)+3(2-9)⇒1(5)-2(1)+3(-7)$
$⇒5-2-21⇒5-23⇒-18≠0$
So value of $9 - 2x ⇒ 9 - 2 × (-18) ⇒ 9 + 36 ⇒ 45$