x^2-4x+1=0x^2=4x-12(x-1)/(x-4) - (x+6)/x=(2x^2-2x - x^2-2x+24) /(x^2-4x) =(x^2-4x+24)/(x^2-4x) = 1 + 24/(x^2-4x) =1 + 24/(-1)=-23
