Answer:
[tex]5\sqrt{5}[/tex]
Step-by-step explanation:
We start by factoring 125 and look for a perfect square:
125= 5*5*5=[tex]5^{2} *5[/tex].
This allow us to simplify the radical:
[tex]\sqrt{125} = \sqrt{5^{2} *5}[/tex]
So we have:
[tex]\sqrt{5^{2} *5} =5\sqrt{5}[/tex]