Помогите сделать алгебру.Зарание спасибо.номер 290 и 291.

$1) frac{4}{a+2}- frac{3}{a-2}+ frac{12}{ a^{2}-4 }= frac{4a-8-3a-6+12}{(a+2)(a-2)}= frac{1}{a+2}$
$2) frac{6m}{m-3}+ frac{m^2+m}{4}* frac{8}{m+1}= frac{2m^2+2m}{m+1} +frac{6m}{m-3}= frac{(2m^2+2m)(m-3+6m(m+1))}{(m-3)(m+1)}=$
$=2m^2+8m$
$3) frac{x}{x-y}- frac{x}{x+y} ): frac{xy}{x+y} = frac{x(x+y-x(x-y))}{(x-y)(x+y)}= frac{2xy}{(y-2)(x+y)}* frac{x+y}{xy} = frac{xy}{x-y}$
$4) frac{y}{2x+2y}+ frac{x}{a-1}* frac{a-1}{2x+2y}= frac{x+y}{2x+2y}= frac{1}{2}=0.5$
№291
$1)( frac{x}{x+1} +1)* frac{x+1}{2x-1}= frac{2x+1}{x+1}* frac{x+1}{2x-1} =frac{2x+1}{2x-1}$
$2) (frac{4y}{2-y}- y): frac{y-2}{y+2} = frac{2y+y^2}{2-y}* frac{y-2}{y+2}= frac{y(2+y)}{y+2}=y$
$3) frac{a+3}{a^2+9}*( frac{a+3}{a-3}+ frac{a-3}{a+3})= frac{a+3}{a^2+9}* frac{2a^2}{(a-3)(a+3)}= frac{2a^2}{(a-3)(a^2+9)}$