Question

simplify the expression: $3\sqrt{3} - \sqrt{27}$

Explanation:

Step1: Simplify $\sqrt{27}$

We know that $27 = 9\times3$, and $\sqrt{ab}=\sqrt{a}\times\sqrt{b}$ (for $a\geq0,b\geq0$). So $\sqrt{27}=\sqrt{9\times3}=\sqrt{9}\times\sqrt{3}=3\sqrt{3}$.

Step2: Substitute and simplify the expression

The original expression is $3\sqrt{3}-\sqrt{27}$. Substitute $\sqrt{27}=3\sqrt{3}$ into it, we get $3\sqrt{3}-3\sqrt{3}$. Then $3\sqrt{3}-3\sqrt{3} = 0$.

Answer:

$0$