We can simplify radicals by factoring the radicand.
If you don't know what a radicand is, it is the number inside the radical.
The number 18 has the factors 6 and 3. But we want one factor when being square rooted be a perfect square.
So, we want to use the factors 9 and 2.
Now it is [tex] \sqrt{9 * 2} [/tex]
And we get the numbers their own radicals.
[tex] \sqrt{9 * 2} = \sqrt{9} \sqrt{2} [/tex]
The [tex] \sqrt{9} [/tex] can be simplfied to 3.
And now we have [tex]3 \sqrt{2} [/tex].
