How to do the 20 13 Zhejiang Mathematics College Entrance Examination 16 question, I feel that the answer is not quite right.
Shilling x= 1, a+b=0.
Let x=- 1 and get a-b=2.
So a = 1 and b =- 1.
So ab=- 1
Is the answer like this? Do you have any questions?