=1/3-(x+1)/x(x+1)-(x-1)/3(x+2)(x-1)
=1/3-1/x-1/3(x+2)
=[x(x+2)-3(x+2)-x]/3(x+2)
=(x²+2x-3x-6-x)/3(x+2)
=(x²-2x-6)/(3x+6)