How do you add and subtract radical expressions?

Question

ivettef365 · Answer

http://www.regentsprep.org/Regents/math/ALGEBRA/AO1/Laddsubt.htm

ivettef365 · Answer

http://www.purplemath.com/modules/radicals3.htm

phi · Answer

if you have two terms with the same radical,  then you can factor out the radical

example:   
$$ 2 \sqrt{3} + 4 \sqrt{3} = (2+4)\sqrt{3}=  6 \sqrt{3} $$

or you can say to yourself:  2 square roots of 3 plus another 4 square roots of 3 gives 6 square roots of 3

anonymous · Answer

Thank you guys, and one more question. Can you show me the simplest way to simplify them?

phi · Answer

lots of times  they disguise the "same radical"

example:
$$ \sqrt{2} + \sqrt{18} $$
but $ \sqrt{18}= \sqrt{9 \cdot 2} = \sqrt{9} \sqrt{2} = 3 \sqrt{2} $
so the problem is really
$$ \sqrt{2} + \sqrt{18}  \  \sqrt{2} +3 \sqrt{2} $$
and the answer is $ 4 \sqrt{2} $

phi · Answer

see this video on the general technique for simplify radicals http://www.khanacademy.org/math/arithmetic/exponents-radicals/radical-radicals/v/square-roots-and-real-numbers