Question

Simplify: (-2i+√5)(-2i-√-5)?

Answer 1

by distributive law
(-2i+√5)(-2i-√-5) = -2i*-2i -2i*-(√-5) + √5* -2i + √5*(-√-5)

Answer 2

note i = √-1, so i^2 = -1

Answer 3

so -2i*-2i = 4 * i^2 = 4 * -1 = -4

Answer 4

and √-5 can be written √5 i

Answer 5

so it be -4+ sqr(5) i

Answer 6

no it just be plus 5..right?

Answer 7

no - i was just helping you do the tricky bits you must simplify what i wrote in my first post

Answer 8

oh..