1<y<2 оцените x+y, xy, y-x, y/x, 3x+y

1 < y < 2, x+y = x + (1 < y < 2) = x + 1 xy = x(1 < y < 2) = x y-x = (1 < y < 2) - x = 1 - x y/x = (1 < y < 2) / x = 1 / x 3x+y = 3x + (1 < y < 2) = 3x + 1