[Math] Simplify Square Root Expression $\sqrt{125} – \sqrt{5}$

Question

$\sqrt{125}-\sqrt5$ simplify it.

I thought it would be $\sqrt {5\cdot5\cdot5}-\sqrt 5$ which would be the square root of 25 which is 5 but it is not.

Can you show how to simplify this?

Answer 1

$\sqrt{125}-\sqrt{5}=\sqrt{5\times 25}-\sqrt{5}=\sqrt{25}\sqrt{5}-\sqrt{5}=5\sqrt{5}-\sqrt{5}=4\sqrt{5}$