a-c=0.5,a+b=0.75,b+c=0.25 求A,B,C

x��PKN�0�J�5 B�ؘH�I�(�T�Q�RH-A��#@T�MC ���W`� v�-[��f�ͣ��l�l6-�4\|�-�6�e"?�%{d��G�:4ӳ���89Kaä�ٙ��B�$��|��U� �lȻNL��z���8�?�L��y9�o�*y�<�Y�Mj{Ρ�+����9d�0˱3g����˒�V�~�L^^ G!�T����R��T�<���ɭ(J2��c����^m���x��0t�W�[�>U���6*�Q�9r��zU�6�l��