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AP EAMCET · Maths · Matrices

If \(Q\) is the inverse of \(A\), when \(A=\left[\begin{array}{ccc}1 & -1 & 1 \\ 2 & 1 & -3 \\ 1 & 1 & 1\end{array}\right]\) and \(10 \times Q=\left[\begin{array}{ccc}4 & 2 & 2 \\ -5 & 0 & x \\ 1 & -2 & 3\end{array}\right]\), find \(x=\)

  1. A 2
  2. B 3
  3. C 4
  4. D 5
Verified Solution

Answer & Solution

Correct Answer

(D) 5

Step-by-step Solution

Detailed explanation

Given, \(Q=A^{-1}\) \(\begin{aligned} A & =\left[\begin{array}{ccc} 1 & -1 & 1 \\ 2 & 1 & -3 \\ 1 & 1 & 1 \end{array}\right] \\ |A| & =1(1+3)+1(2+3)+1(2-1)=4+5+1 \\ |A| & =10 \end{aligned}\)…