F(X)=0.25X方-1.5X+1.25
f(2x-1)=0.25(2x-1)^2-1.5(2x-1)+1.25
=0.25(4x^2-4x+1)-(3x-1.5)+1.25
=x^2-x+0.25-3x+1.5+1.25
=x^2-4x+3