Segrif 1)
x + y - xy = -2 | x + y = xy - 2
xy(x + y) = 48
xy*(xy - 2) = 48
(xy)^2 - 2xy - 48 = 0
(xy + 6)*(xy - 8) = 0
xy = {-6, 8}
a) xy = -6, y = -6/x
x + y - xy = -2
x - 6/x + 6 = -2
x^2 - 4x + 8 = 0
(x - 2)^2 + 4 = 0 -> нет вещественных решений
б) xy = 8, y = 8/x
x + y - xy = -2
x^2 + 8/x - 8 = -2
x^2 - 6x + 8 = 0
(x - 2)(x - 4) = 0
x = 2, y = 8/2 = 4
x = 4, y = 8/4 = 2

2)
x^2 - xy + y = 16
3y - x = 14 | y = (x + 14)/3
x^2 - x(x+14)/3 + (x+14)/3 = 16
3x^2 - x^2 - 14x + x + 14 = 48
2x^2 - 13x - 34 = 0
(2x - 17)(x + 2) = 0
x = -2, y = 12/3 = 4
x = 8.5, y = 22.5 / 3 = 7.5