What is the sum of √-2 and √-18

a. 4 √2

b. 4 √2i

c. 5 √2

d. 5 √2i

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.