First, it is necessary to take out the i from the root. This is done by factoring out -1 as follows, using the relation √(-1) : = i
√-2 = √(-1)(2) = i√2
√-18 = √(-1)(2)(9) = 3i√2
Simplifying by adding the two terms together:
i√2 + 3i√2 = 4i√2
Therefore the answer is B.