Invers matriks A = ( -4 -5 ) adalah... ( 2 3 )

A = [tex] \left[\begin{array}{cc}-4&-5\\2&3\end{array}\right] [/tex]

det(A) = -12 - (-10) = -2

Adj(A) = [tex]\left[\begin{array}{cc}3&5\\-2&-4\end{array}\right][/tex]

Invers(A) = 1/det(A) . Adj(A)
= [tex] -\frac{1}{2} \left[\begin{array}{cc}3&5\\-2&-4\end{array}\right]\\=\left[\begin{array}{cc}- \frac{3}{2} &- \frac{5}{2} \\1&2\end{array}\right][/tex]