=1/(x-5)-6/(x+5)(x-5)-(x+1)/2(x+5)
=2(x+5)/2(x+5)(x-5)-12/2(x+5)(x-5)-(x+1)(x-5)/2(x+5)(x-5)
=(2x+10-12-x²+4x+5)/2(x²-25）
=(-x²+6x+3)/(2x²-50)
=-(x²-6x-3)/(2x²-50)