Matrix to Inverse (2x2, with Formula)

Question

Which is the inverse of this matrix? Use $A^{-1} = \frac{1}{\vert A \vert} 	ext{adj}(A)$.

$$\left[ {\begin{array} {cc}  9 &  4 \ 4 &  -1 \end{array}  } ight]$$

Accepted Answer

$$\left[ {\begin{array} {cc}  -0.36 &  -0.16 \ -0.16 &  0.04 \end{array}  } ight]$$

Answer

$$\left[ {\begin{array} {cc}  -0.36 &  -0.16 \ -1.16 &  -0.96 \end{array}  } ight]$$

Answer

$$\left[ {\begin{array} {cc}  -0.36 &  -0.16 \ -0.16 &  2.04 \end{array}  } ight]$$

Answer

$$\left[ {\begin{array} {cc}  -0.36 &  -1.16 \ 1.84 &  0.04 \end{array}  } ight]$$

Practice: Matrices