The number of minor repairs is:? x+3

Xiaochang's book revision amount is 0.4x-2.

Mr. Wu has repaired 20 books.

∴ ? x+3+0.4x-2+20=x

0.65x+2 1=x

Solve the equation and get x=60.

There are 60 damaged books.

Xiao Fang fixed it? *60+3= 18 (Ben), and the small patch is 0.4*60-2=22 (Ben).

I hope you can adopt it.