Первая система:
1) y-x = 1 => y = 1 + x
2) 2*(1+x)*x = 4 => 2*(x+x^2) = 4 => x+x^2 = 2 => x^2 + x - 2 = 0 => x1 = 1, x2 = -2.
x1 = 1, y1 = 2; x2 = -2, y2 = -1
Вторая система:
1) x + y = 6 => y = 6 - x
2) x^2 - 6 + x = 6 = > x^2 + x - 12 = 0 => x1 = -4, x2 = 3
x1 = -4, y1 = 10; x2 = 3, y2 = 3