[tex] a)Ex=x-( \frac{1}{x-3}+ \frac{7- x^{2} }{x-1}* \frac{1}{x-3}): \frac{x+2}{2(x-1)}= \\ =x-( \frac{1}{x-3}+ \frac{7- x^{2} }{(x-1)(x-3)}): \frac{x+2}{2(x-1)}= \\ =x-( \frac{x-1+7- x^{2} }{(x-1)(x-3)}): \frac{x+2}{2(x-1)}= \\ =x- \frac{-( x^{2}-x-6) }{(x-1)(x-3)}* \frac{2(x-1)}{x+2}=x+ \frac{(x-3)(x+2)}{(x-1)(x-3)}* \frac{2(x-1)}{x+2}= \\ =x+2 [/tex]