<s>[INST] Simplify Square Root Expression $\sqrt{125} - \sqrt{5}$ $\sqrt{125}-\sqrt5$ 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?
 [/INST] \begin{align}
\sqrt{125}-\sqrt{5}&=\sqrt{5^3}-\sqrt{5}\\
                   &=\sqrt{5^2\cdot 5}-\sqrt{5}\\
                   &=\sqrt{5^2}\sqrt{5}-\sqrt{5}\\
                   &=5\sqrt{5}-\sqrt{5}\\
                   &=4\sqrt{5}
\end{align}
</s>