# How do you simplify 2 sqrt2 +sqrt18?

I found $5 \sqrt{2}$
We can write $18 = 2 \cdot 9$ and so:
$2 \sqrt{2} + \sqrt{2 \cdot 9} = 2 \sqrt{2} + \sqrt{2} \sqrt{9} = 2 \sqrt{2} + 3 \sqrt{2} = 5 \sqrt{2}$