3. (3 points) Define a new operation: , find the value of:
Translate the above text into English, please retain the original text's line breaks and format, and output the translation result directly.
3. (3 points) Define a new operation: , find the value of:
Translate the above text into English, please retain the original text's line breaks and format, and output the translation result directly.
3. (3 points) Define a new operation: , find: , the value is 3 .
【Solution】Solution: ,
Therefore, the answer is: 3 .