The integral is approached by substituting \( u = x - 3 \), leading to \( x = u + 3 \) and \( dx = du \). This transforms the integral into \( \int (u + 3)u^{1/2} du \), which simplifies to \( \int u^{3/2} + 3u^{1/2} du \). The resulting integral evaluates to \( \frac{2}{5}u^{5/2} + 2u^{3/2} + C \). Substituting back for \( u \) gives the final result as \( \frac{2}{5}(x - 3)^{5/2} + 2(x - 3)^{3/2} + C \). The method effectively demonstrates the use of substitution in solving integrals.