MCQ
If $A=\left[\begin{array}{ll}2 & -3 \\ 5 & -7\end{array}\right]$, then $A-A^{-1}=$
  • A
    $\left[\begin{array}{cc}-5 & 0 \\ 0 & -5\end{array}\right]$
  • B
    $3\left[\begin{array}{cc}3 & 2 \\ 10 & 3\end{array}\right]$
  • $3\left[\begin{array}{cc}3 & -2 \\ \frac{10}{3} & -3\end{array}\right]$
  • D
    $5\left[\begin{array}{ll}1 & 2 \\ 3 & 4\end{array}\right]$

Answer

Correct option: C.
$3\left[\begin{array}{cc}3 & -2 \\ \frac{10}{3} & -3\end{array}\right]$
(c) : Given, $A=\left[\begin{array}{ll}2 & -3 \\ 5 & -7\end{array}\right]$, then $A^{-1}=\left[\begin{array}{ll}-7 & 3 \\ -5 & 2\end{array}\right]$
Now, $A-A^{-1}=\left[\begin{array}{ll}2 & -3 \\ 5 & -7\end{array}\right]-\left[\begin{array}{ll}-7 & 3 \\ -5 & 2\end{array}\right]$
$
=\left[\begin{array}{cc}
9 & -6 \\
10 & -9
\end{array}\right]=3\left[\begin{array}{cc}
3 & -2 \\
10 / 3 & -3
\end{array}\right]
$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free