F'(x)=((3x-1)*2x-(x^2-4)*3)/(3x-1)^2=(6x^2-2x-3x^2+12)/(3x-1)^2=(3x^2-2x+12)/(3x-1)^2 f'(1)=(3-2+12)/(3-1)^2=13/4=3,25