Exponents and logarithms and radical numbers...sooo simplify the expression nr.2

Question

anonymous · Answer

$$2\sqrt{8}+\sqrt{200}-4\sqrt{18}$$

anonymous · Answer

The only way you can simplify is after you simplify the radicals.

anonymous · Answer

$$
2\sqrt{8}=2\sqrt{2\cdot 2\cdot 2}=2\cdot 2\sqrt{2}=4\sqrt{2}
$$

anonymous · Answer

$$
\sqrt{200} = \sqrt{2\cdot 2\cdot 2\cdot 5\cdot 5}=5\cdot 2\sqrt{2}=10\sqrt{2}
$$

anonymous · Answer

Now you need to do the same with $$
4\sqrt{18} 
$$But do it yourself this time for practice.

anonymous · Answer

yeah I got the same thing,but I don't know how to do with $$4\sqrt{18}$$ should it be 
$$4\sqrt{9}\times \sqrt{2}$$? and soo? @wio

anonymous · Answer

Okay what is the prime factorization of $18$?

anonymous · Answer

Oh wait, what you have is fine, but you need to change $\sqrt{9}=\sqrt{3\cdot 3}=3$

anonymous · Answer

ohh thanks that's why I got the wrong answer hehe ^^