Решите систему уравнений:

$\left \{ {{x^{2}+10xy+25y^{2}=9} \atop {x-5y=7}} \right.\\\\\left \{ {{(x+5y)^{2}=9 } \atop {x-5y=7}} \right.\\\\1)+\left \{ {{x+5y=-3} \atop {x-5y=7}} \right.\\ --------\\2x=4\\\\x_{1} =2\\\\2-5y=7\\\\5y=-5\\\\y_{1}=-1 \\\\2)+\left \{ {{x+5y=3} \atop {x-5y=7}} \right.\\-------\\2x=10\\\\x_{2}=5\\\\5-5y=7\\\\5y=-2\\\\y_{2}=-0,4$

Ответ : (2 ; - 1) , (5 ; - 0,4)