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COMEDK · Maths · 21. Matrices

What must be the matrix \(X\) if \(2 X+\left[\begin{array}{ll}1 & 2 \\ 3 & 4\end{array}\right]=\left[\begin{array}{ll}3 & 8 \\ 7 & 2\end{array}\right] ?\)

  1. A \(\left[\begin{array}{cc}1 & 3 \\ 2 & -1\end{array}\right]\)
  2. B \(\left[\begin{array}{ll}1 & -3 \\ 2 & -1\end{array}\right]\)
  3. C \(\left[\begin{array}{cc}2 & 6 \\ 4 & -2\end{array}\right]\)
  4. D \(\left[\begin{array}{ll}2 & -6 \\ 4 & -2\end{array}\right]\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(\left[\begin{array}{cc}1 & 3 \\ 2 & -1\end{array}\right]\)

Step-by-step Solution

Detailed explanation

We have, \(2 X+\left[\begin{array}{ll}1 & 2 \\ 3 & 4\end{array}\right]=\left[\begin{array}{ll}3 & 8 \\ 7 & 2\end{array}\right]\) \(\Rightarrow \quad 2 X=\left[\begin{array}{ll}3 & 8 \\ 7 & 2\end{array}\right]-\left[\begin{array}{ll}1 & 2 \\ 3 & 4\end{array}\right]\)…