（x-1）/﹙x²+3x+2﹚- 6/﹙x²-x-2﹚ -﹙x-10﹚/﹙x²-4﹚

=(x-1)/(x+2)(x+1)-6/(x-2)(x+1)-(x-10)/(x+2)(x-2)
=[(x+1)(x-2)-6(x+2)-(x-10)(x+1)]/ (x+2)(x+1)(x-2)
=(x²-x-2-6x-12-x²+9x+10)/(x+2)(x+1)(x-2)
=(2x-4)/(x+2)(x+1)(x-2)
=2/(x+2)(x+1)