Решите систему уравнений 7x-5y = 8 x+y = 1 целая 3/35

Решите задачу:

$\left \{ {{7x-5y=8} \atop {x+y=1 \frac{3}{35} }} \right. \left \{ {{7x-5y=8} \atop {5x+5y=5 \frac{3}{7} }} \right. \\\\ 7x+5x=8+5 \frac{3}{7} \\\\ 12x=13 \frac{3}{7} = \frac{94}{7} \\\\ x= \frac{94}{12*7} = \frac{47}{6*7} = \frac{47}{42} \\\\ 7* \frac{47}{42} -5y=8\\\\ \frac{47}{6} -5y=8\\\\ 5y= \frac{47}{6} -8= \frac{47-8*6}{6} =- \frac{1}{6} \\\\ y= -\frac{1}{6*5} =- \frac{1}{30}$