Show That B Is the Inverse of A ​

Essay

Show that B is the inverse of A.Show all your work. $A = \left[ \begin{array} { c c } 2 & 9 \\- 4 & 3\end{array} \right] , B = \left[ \begin{array} { c c } \frac { 1 } { 14 } & - \frac { 3 } { 14 } \\\frac { 2 } { 21 } & \frac { 1 } { 21 }\end{array} \right]$ ​