ax+ 1 & gt； 0x & gt； - 1/a

f'(x)=a/(ax+ 1)+2x-a=(2ax^2+2x-a^x-a+a)/(ax+ 1)

=(ax^2+2x)/(ax+ 1)

When x>0, f' (x) >; 0, the function is increased; When-1/a

(2) a = 1, f (x) = ln (x+ 1)+x 2-x-m has 1 positive roots and two (-1, 0) roots.

F(0) is the minimum value,-m.