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GATE 2026 ES – Question 11

Mathematics Foundation · Linear Algebra · 1 mark · Multiple choice

Find the matrix $X$ satisfying $$2X+\begin{pmatrix}1&2\\3&4\end{pmatrix}=\begin{pmatrix}3&8\\7&2\end{pmatrix}.$$

  1. $\begin{pmatrix}2&5\\5&3\end{pmatrix}$
  2. $\begin{pmatrix}-1&3\\2&-1\end{pmatrix}$
  3. $\begin{pmatrix}1&3\\2&-1\end{pmatrix}$
  4. $\begin{pmatrix}1&0\\0&1\end{pmatrix}$

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Correct answer: (C) $\begin{pmatrix}1&3\\2&-1\end{pmatrix}$

Explanation

Subtract the known matrix entry by entry to obtain $2X=\begin{pmatrix}2&6\\4&-2\end{pmatrix}$. Divide every entry by 2: $X=\begin{pmatrix}1&3\\2&-1\end{pmatrix}$. Substitution recovers the original equation. Hence **C**.

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