Помогите решить задание из гиа по математике!

$\left \{ {{x-y=7} \atop { x^{2} + y^{2} =9-2xy}} \right. \left \{ {{x=7+y} \atop { x^{2} +2xy+ y^{2}-9 =0}} \right. \left \{ {{x=7+y} \atop { (x+ y)^{2}-9 =0}} \right. \left \{ {{x=7+y} \atop { (x+ y-3)(x+y+3) =0}} \right.$ $\left \{ {{x=7+y} \atop { (7+y+ y-3)(7+y+y+3) =0}} \right. \left \{ {{x=7+y} \atop { (7+2y-3)(7+2y+3) =0}} \right.$

*7+2y-3=0
4+2y=0
y=-4:2
y₁=-2
*7+2y+3=0
10+2y=0
y=-10:2
y₂=-5.
x₁=7+(-2)
x₁=5
x₂=7+(-5)
x₂=2.
Ответ:x₁=5;y₁=-2;
x₂=2;y₂=-5.