# How do you factor by grouping t^3-t^2+t-1?

${t}^{3} - {t}^{2} + t - 1 = \left({t}^{3} - {t}^{2}\right) + \left(t - 1\right)$
$= {t}^{2} \left(t - 1\right) + 1 \left(t - 1\right) = \left({t}^{2} + 1\right) \left(t - 1\right)$.
Since ${t}^{2} + 1 > 0$ for all real values of $t$, there are no smaller factors with real coefficients.