Chapter 6, Matrices and Determinants - Section 6.3 - Inverses of Matrices and Matrix Equations - 6.3 Exercises - Page 523: 17

\[ M= \left[ {\begin{array}{cc} 1 & 2 \\ -0.5 & 2/3 \\ \end{array} } \right] \]

The determinant is $.24+.36 = 0.6$ Plugging this... \[ M= 1/0.6 \left[ {\begin{array}{cc} 0.6 & 1.2 \\ -0.3 & 0.4 \\ \end{array} } \right] \] \[ M= 5/3 \left[ {\begin{array}{cc} 0.6 & 1.2 \\ -0.3 & 0.4 \\ \end{array} } \right] \]\ \[ M= \left[ {\begin{array}{cc} 1 & 2 \\ -0.5 & 2/3 \\ \end{array} } \right] \]