If $X+Y=\left[\begin{array}{ll}2 & 1 \\ 3 & 5\end{array}\right]$ and $X-Y=\left[\begin{array}{ll}0 & 3 \\ 7 & 9\end{array}\right]$, then $Y$ is equal to
Answer & explanation
Correct answer: option 3
$X+Y=\left[\begin{array}{ll}2 & 1 \\ 3 & 5\end{array}\right]$ .....(1)
$X-Y=\left[\begin{array}{ll}0 & 3 \\ 7 & 9\end{array}\right]$ .....(2)
eq. (1) - eq. (2)
⇒ 2Y = $\left[\begin{array}{cc}2 & -2 \\ -4 & -4\end{array}\right]$ so $Y=\left[\begin{array}{cc}1 & -1 \\ -2 & -2\end{array}\right]$
→ Option C