Алгебра 7 класс 290 упражнение помогите пожалуйста

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