[(x-2)/(x^2+2X)-(x-1)/(x^2+4x+4)]÷(x-4)/(x+2),=[(x-2)/x(x+2)-(x-1)/(x+2)^2)]÷(x-4)/(x+2)=[(x-2)(x+2)-x(x-1)](x+2)}/x(x+2)^2(x-4)=(-4+x)/x(x+2)(x-4)=-1/(x^2+2x)=-1/(1)=-1