50 баллов!!! Пожалуйста!!! Спасибо!!!

1) $\frac{4(a-2)}{a^2-4} - \frac{3(a+2)}{a^2-4} + \frac{12}{a^2-4}= \frac{4a-8-3a-6+12}{a^2-4} = \frac{a-2}{a^2-4}= \frac{1}{a+2}$
2) $\frac{6m}{m-3} + \frac{m(m+1)}{4} * \frac{8}{m+1} = \frac{6m}{m-3} +2m= \frac{6m+2m^2-6m}{m-3}= \frac{2m^2}{m-3}$
3) $\frac{x^2+xy-x^2+xy}{x^2-y^2} * \frac{x+y}{xy} = \frac{2xy}{(x+y)(x-y)} *\frac{x+y}{xy}= \frac{2}{x-y}$
4) $\frac{y}{2(x+y)} + \frac{x}{2(x+y)} = \frac{x+y}{2(x+y)} = \frac{1}{2}$