if(2x- 1)>； (x- 1),f(x)=(x- 1)^2-(2x- 1)(x- 1)=-x^2+3x+ 1

2x^2-x=m

-x 2+3x+ 1 = m，

2x^2-x-m=0

X 2-3x+M- 1 = 0 has three unequal real roots.

Vieta's theorem can be used to find out.