2 / 2 \ 2 \x - 3*x/ < 12 - 3*x + x
(x^2 - 3*x)^2 < x^2 + 12 - 3*x
And(-1 < x, x < 4)
(-1 < x)∧(x < 4)
(-1, 4)
x in Interval.open(-1, 4)