Pls solve.this equarion here v and u is speed.and L is the width it is of physics

Dear Student,
Your question is not clear and appears to be incomplete.
This is not an equation as it need to be equated with some factor (either a constant or another function)
The above expression can be simplified as follows:
$$\begin{gathered} \left(u-v\left(\frac{v}{u}\right)\right)\left(\frac{uL}{v\sqrt{u^2-v^2}}\right) \\ =\left(\frac{u^2-v^2}{u}\right)\left(\frac{uL}{v\sqrt{u^2-v^2}}\right) \\ =\left(\sqrt{u^2-v^2}\right)\left(\frac{L}{v}\right) \\ =\left(\frac{L}{v}\right)\left(\sqrt{u^2-v^2}\right) \end{gathered}$$
Recheck your question or please be a little specific about the name of the chapter/textbook to which you are referring here so that we
can provide you with some meaningful help.
Look forward to hearing from you again!
Regards