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Multiply (9-4i)(2+5i)

1 Answer

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(9 - 4i)(2 + 5i)

To solve this question you must FOIL (First, Outside, Inside, Last) like so

First:

(9 - 4i)(2 + 5i)

9 * 2

18

Outside:

(9 - 4i)(2 + 5i)

9 * 5i

45i

Inside:

(9 - 4i)(2 + 5i)

-4i * 2

-8i

Last:

(9 - 4i)(2 + 5i)

-4i * 5i

-20i²

Now combine all the products of the FOIL together like so...

18 + 45i - 8i - 20i²

***Note that i² = -1; In this case that means -20i² = 20

18 + 45i - 8i + 20

Combine like terms:

38 - 37i

^^^This is your answer

Hope this helped!

~Just a girl in love with Shawn Mendes

User Kranthi Guttikonda
by
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