If $A=\left[\begin{array}{ll}2 & 3 \ 5 & 7\end{array} ight]$ then $A(\operatorname{adj} A)$ is

Question

If $A=\left[\begin{array}{ll}2 & 3 \ 5 & 7\end{array}ight]$ then $A(\operatorname{adj} A)$ is

Professor PC Thomas Classes · Answer

Fundamental identity $A(	ext{adj} A) = |A|I$. $|A| = 14-15 = -1$, yielding $-I$.