TeX source:

\int_{x=0}^{x=1}(3 x-1)^{4} \mathrm{dx}=\int_{u=-1}^{u=2} u^{4} \frac{1}{3} \mathrm{du}=\left.\frac{1}{15} \mathrm{u}^{5}\right|_{-1} ^{2}=\frac{1}{15}(2)^{5}-\frac{1}{15}(-1)^{5}=\frac{32}{15}-\frac{-1}{15}=\frac{33}{15}