Question 303138
square root of (-4) x square root of (-4)

square root of -1 is i
square root of 4 is +- 2
so square root of -4 is +- 2i
3 possibilites: 1. take + root times + root and get - answer
                2. - root times - root and get - answer (same answer as 1.)
                3. + root times - root or vice versa and get + answer
(the i^2 flips the sign)
so 2 answers: 1. 2i * 2i = -2i * -2i = 4i^2 = 4 * -1 = -4
              2. 2i * -2i = -2i * 2i = -4i^2 = -4 * -1 = 4