[tex] \frac{(x-1)(x-1)-(x+1)(x+1)}{(x+1)(x-1)} [/tex] · [tex] \frac{x(x+1)}{8} [/tex]
·[tex] \frac{ (x-1)^{2}- (x+1)^{2} }{(x+1)(x-1)} [/tex][tex] \frac{x(x+1)}{8} [/tex]=
[tex] \frac{ x^{2}-2x+1- x^{2} -2x-1}{x-1} [/tex]·[tex] \frac{x}{8} [/tex]=
[tex] \frac{-4x-2}{x-1} [/tex]·[tex] \frac{x}{8} [/tex]=
[tex] \frac{-x(2x+1)}{4(x-1)} [/tex]
