1) x² + 3xy + y² = 61 2) x² + 3xy + y² = 61 3) x² + 3xy + y² = 61
2xy = 24 xy = 12 3xy = 36
4) x² + 36 + y² = 61 5) x² + y² = 25
2xy = 24 +
2xy = 24
______________
x² + 2xy + y² = 49
(x + y)² = 49
6) x + y = 7 7) x + y = - 7
xy = 12 xy = 12
x = 4, y = 3 x = - 4, y = - 3
x = 3, y = 4 x = -3, y = - 4 по теореме Виетта
Ответ: (-4;-3),(-3;-4)(4;3),(3;4)