t*(t + 3) > 0
Or(And(-oo < t, t < -3), And(0 < t, t < oo))
((-oo < t)∧(t < -3))∨((0 < t)∧(t < oo))
(-oo, -3) U (0, oo)
x in Union(Interval.open(-oo, -3), Interval.open(0, oo))