Euler's substitution might just work!

Calculus Level 5

$\large \displaystyle \large \int_{0}^{4} \dfrac{\sqrt{x^{2}+9} \left (x+\sqrt{x^{2}+9}\right)}{\sqrt{x^{2}+9}-x} \, dx$

Find the value of the closed form of the above integral to 3 decimal places.