That doesn't factor, because none of the 8 potential "P/Q" roots work: ±1, ±1/3, ±1/9, ±/27 So the only way to approximate the irrational roots is with a TI-calculator x ≈ -1.113001292 x ≈ -0.3769893968 The approximations for the two conjugate complex roots are x ≈ 0.24499534428 ± 0.1680682506i Are you sure you didn't make a mistake in copying one of the coefficients or signs? Edwin