C330 Extension of the Multi-variable Function

... "" What do you mean by a slap to the head to prove a conjecture? I spent a "huge sum" okay?

God knows how many brain cells he lost for the sake of earning a little Study Achievement Point.

"Teacher Feng, perhaps you don't know. Actually, I am also quite tired." Qin Luo said.

Tired?

Feng Huadong's brain heated up, and he almost slapped Qin Luo's face