simplify. \n$9\\sqrt{18}$

Explanation:

Step1: Factor the radicand

Factor 18 into $9\times2$, so $\sqrt{18}=\sqrt{9\times2}$.

Step2: Simplify the square root

Using the property $\sqrt{ab}=\sqrt{a}\times\sqrt{b}$ (where $a = 9$, $b = 2$), we get $\sqrt{9\times2}=\sqrt{9}\times\sqrt{2}=3\sqrt{2}$.

Step3: Multiply by the coefficient

Multiply 9 by $3\sqrt{2}$: $9\times3\sqrt{2}=27\sqrt{2}$.

Answer:

$27\sqrt{2}$