Question

(-2i)(5i)(-1) how do you solve by simplifying showing the steps

Answer 1

$i = \sqrt{-1}$

This is the fundamental property of i that you'll need to keep in mind when solving any problem with imaginary numbers (5i, 2i, 18i, etc.) or complex numbers (3+2i, 8-5i, etc). Squaring both sides of this definition, we also get that

$i^2=-1$

Which we can use to solve this problem. We have:

$(-2i)(5i)(-1)\\ =(-10i^2)(-1)\\ =(-10)(-1)(-1)\\ =-10$