The constant term in this quartic equation is (-2)² - 2 = 2. This being the case, if there are rational roots, then they are x = ±1 or ±2. By observation, x = -1 and x = 2 are in fact roots. We can expand out the quartic and then divide it by (x + 1)(x - 2) = x² - x - 2 to find the remaining quadratic factor, which can easily be solved.