\( \int \frac{5}{7}(3 x)^{1 / 4} d x \)
\( =\frac{5}{7} \int(3 x)^{1 / 4} d x \)
\( =\frac{5}{7} \int(3)^{1 / 4} · x^{1 / 4} d x \)
\( =\frac{5}{7} \cdot \sqrt[4]{3} \int x^{\frac{1}{4}} d x \)
\( =\frac{5}{7} \cdot \sqrt[4]{3} \cdot \frac{4}{5} \cdot x^{5 / 4}+c \)
\( =\frac{4}{7} \sqrt[4]{3} · x^{5 / 4}+c \)