When multiplying (8i)(4i)(9i), you can multiply (8i)(4i), which is equal to -32. You then multiply (-32)(9i), which equals -288i. However, if you chose to multiply (4i)(9i) = -36, and then multiply (-36)(8i) you also get -288i.
-288i is the final answer.
Happy break to my students! You have one less semester left in the year. You want to stay sharp over the break in order to start the next semester strong. Here are my three tips for staying sharp over the break.
Keep Practicing: Concepts in math build upon each other. Was there something you didn't understand in the first semester? Be sure to keep practicing...