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anonymous

  • 5 years ago

find the product for (5+3i)(5-3i)... I got 24-9a. Does anyone know if this is correct?

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  1. anonymous
    • 5 years ago
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    Should be 25-9i. You use foil if you've ever been taught that.

  2. anonymous
    • 5 years ago
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    No i, my bad.

  3. anonymous
    • 5 years ago
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    yeah, that's what I used.. and since the 9i was squared i added a -1. must have calculated it our wrong. Thanks

  4. anonymous
    • 5 years ago
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    yeah, do the i's cancel out? So it would be 25-9?

  5. anonymous
    • 5 years ago
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    And actually should be adding. Let's start over lol.

  6. anonymous
    • 5 years ago
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    ha good call!

  7. anonymous
    • 5 years ago
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    25-9i^2. That is what you should get, which can be simplified.

  8. anonymous
    • 5 years ago
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    ok so I can add the 2 and the 25?

  9. anonymous
    • 5 years ago
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    Ok. So i represents an imaginary number, it's what you get when you take the square root of a negative number. And the ^ is raised to a power. So we have 25-9i^2. So if \[i=\sqrt{-1}\] then \[i^2=-1\] So we get 25-9(-1)

  10. anonymous
    • 5 years ago
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    someone help me

  11. anonymous
    • 5 years ago
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    ok so would that be the answer? or can I simplify from there? Since there aren't any i's do I need to add those all to get one number?

  12. anonymous
    • 5 years ago
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    Yes to more simplifying. 25-9(-1) is the same as 25+9=34

  13. anonymous
    • 5 years ago
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    oh so the answer should be just 34?

  14. anonymous
    • 5 years ago
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    Yep.

  15. anonymous
    • 5 years ago
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    Thanksabunch

  16. anonymous
    • 5 years ago
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    No problem. :)

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