Đáp án:
Coi (3x+5) là u thì d(3x+5) = 3dx
Nên phải chia cho 3
$\begin{array}{l}
\int {{{\left( {3x + 5} \right)}^{\frac{1}{2}}}dx} \\
= \int {{{\left( {3x + 5} \right)}^{\frac{1}{2}}}.\frac{1}{3}.3dx} \\
= \int {\frac{1}{3}.{{\left( {3x + 5} \right)}^{\frac{1}{2}}}.d\left( {3x + 5} \right)} \\
= \frac{1}{3}....
\end{array}$