In Algebra 2, I am stuck on understanding how Sal distributes the numbers around 8:08 of the Quadratic Equation with Complex Solutions video.
2(3+i/2)^2 +5 = 6 (3+i/2)
Don't you have to square the 3 and i and then multiply both by 2?
9+i^2/4
18+2i^2/4
Then divide it all by 4?
In the video the i is not squared though, so I must be misunderstanding how to distribute?
Hi Kelsey,
You're on the right track. Just remember,
1) When you square a quantity in parenthesis, both the numerator and denominator get squared, so (3+i/2)^2 becomes (3+i)^2 / 2^2. Then you could foil (3+i)^2.
2) Since i = √-1, i^2 = -1. This may help you when simplifying, and explain why i^2 was missing in the video.
I should note that although it is perfectly fine to ask this question here, it may prove more helpful to ask these types of questions on Khan Academy, and particularly the video in question. That way anyone answering has the video for reference (and you may get a quicker response, as a higher volume of users answer questions on KA rather than the help center).
Hope this helps! Let me know if you have any other questions.
~ Elijah
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