X - 5y = 9
x^2 + 3xy -y^2 = 0
x = 9 + 5y
81 + 90y + 25y^2 + 27y + 15y^2 - y^2 =0
x = 9 + 5y
39y^2 + 117y + 81 = 0
x = 9 + 5y
y = (+-√(1053) - 117)/78
x = 9 + 5y
y1 = (√(1053)-117)/78
y2 = -(√(1053)+117)/78
x1 = 9 + 5(√(1053)-117)/78
x2 = 9 - 5(√(1053)+117)/78
y1 = (√(1053)-117)/78
y2 = -(√(1053)+117)/78
Ответ:{(9 + 5(√(1053)-117)/78;(√(1053)-117)/78);(9 - 5(√(1053)+117)/78;-(√(1053)+117)/78)}