If $A=\left[\begin{array}{ll}2 & -3 \ 5 & -7\end{array} ight]$, then $2 A-3 A^{-1}=$

Question

If $A=\left[\begin{array}{ll}2 & -3 \ 5 & -7\end{array}ight]$, then $2 A-3 A^{-1}=$

Aicharya · Accepted Answer

$A=\left[\begin{array}{ll}2 & -3 \ 5 & -7\end{array}ight] \Rightarrow|A|=-14+15=1$ $	herefore A^{-1}=\left[\begin{array}{cc}-7 & 3 \ -5 & 2\end{array}ight] \quad$ and $\quad 2 A=\left[\begin{array}{cc}4 & -6 \ 10 & -14\end{array}ight]$ $	herefore 2 A-3 A^{-1}=\left[\begin{array}{cc}4-(-21) & -6-9 \ 10-(-15) & -14-6\end{array}ight]=\left[\begin{array}{cc}25 & -15 \ 25 & -20\end{array}ight]$

If $A=\left[\begin{array}{ll}2 & -3 \\ 5 & -7\end{array}\right]$, then $2 A-3 A^{-1}=$

Solution