www . seprodstore . com 83 7 3 . Let 2 3 2 3 3 4 2 1 2 � � � � � � � � � � � � � A and 10 7 2 5 9 6 4 3 8 � � � � � � � � � � � � � � B . ( a ) Write down �1 A . [ 2 ] It is given that 1 1 2 � � A CA B , where C is a 3 3 � matrix . ( b ) Find C . [ 3 ] 4 . Let 0 4 5 0 2 3 1 5 7 � � � � � �� � � � � � A and 1 2 1 3 3 2 0 0 1 � � � � � � � � � � � � � B . ( a ) Write down �1 A . [ 2 ] It is given that 1 3 � � ACA B , where C is a 3 3 � matrix . ( b ) Find C . [ 3 ]