Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Determinants

Question:

If \(x=\begin{bmatrix}1 & 2 & 3\\2 & 3 & 1\\3 & 1 & 2\end{bmatrix}\) then value of 9 - 2x is:

Options:

27

-36

45

-54

Correct Answer:

45

Explanation:

$|x|=1(6-1)-2(4-3)+3(2-9)⇒1(5)-2(1)+3(-7)$

$⇒5-2-21⇒5-23⇒-18≠0$

So value of $9 - 2x ⇒ 9 - 2 × (-18) ⇒ 9 + 36 ⇒ 45$