7 класс. Помогите срочно!!![latex]\left \{ {{ \frac{1}{m}+ \frac{1}{n}=-1 } \atop { \frac{3}{m}- \frac{2}{n}=7  }} \right. [/latex]

[latex]\frac{1}{m} + \frac{1}{n} =-1 \\ \\ \frac{3}{m} - \frac{2}{n} =7 \\ \\ \frac{2}{m}+ \frac{2}{n} =-2 \\ \\ \frac{3}{m} - \frac{2}{n} =7 \\ \\ \\ \frac{2}{m} + \frac{3}{m} =7-2 \\ \\ \frac{5}{m} =5 \\ \\ m=1 \\ \\ \frac{1}{1} + \frac{1}{n} =-1 \\ \\ 1+ \frac{1}{n} =-1 \\ \\ \frac{1}{n} =-2 \\ \\ n=- \frac{1}{2} =-0.5 \\ \\ m=1 \\ n=-0.5[/latex]