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anonymous

  • 5 years ago

divide and rationalize 3+sqrt(18)/ 1+sqrt(8)

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  1. anonymous
    • 5 years ago
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    hey, how's it going?

  2. anonymous
    • 5 years ago
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    hi can you help me?

  3. anonymous
    • 5 years ago
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    sure, first do you know how to simplify sqrt(18) and sqrt(8)?

  4. anonymous
    • 5 years ago
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    yes i simplified the problem to \[3+3\sqrt{2}/1+2\sqrt{2}\]

  5. anonymous
    • 5 years ago
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    good!

  6. anonymous
    • 5 years ago
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    when you have a square root in the denominator, to clean it up you have to multiply by something called the conjugate, which basically just means you change the sign of the square root term

  7. anonymous
    • 5 years ago
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    i did that too.

  8. anonymous
    • 5 years ago
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    so for this case, you would multiply it by (1-2sqrt(2))/(1-2(sqrt(2))

  9. anonymous
    • 5 years ago
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    \[1-2\sqrt{2}\] right?

  10. anonymous
    • 5 years ago
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    right, so did you multiply the top and bottom by that?

  11. anonymous
    • 5 years ago
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    i did but i erased it.

  12. anonymous
    • 5 years ago
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    but just foil right? i get the top part but the bottom confuses me.

  13. anonymous
    • 5 years ago
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    what confuses you about the bottom part? what did you get for the top?

  14. anonymous
    • 5 years ago
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    i got \[3-6\sqrt{2}+6\sqrt{2}-12\] simplified to -9

  15. anonymous
    • 5 years ago
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    WHat hold on somyjing looks rwong

  16. anonymous
    • 5 years ago
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    thats what i figured i got everything till the foiling part

  17. anonymous
    • 5 years ago
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    bob how did you do this

  18. anonymous
    • 5 years ago
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    2sqrt(2)*3sqrt(2) is what?

  19. anonymous
    • 5 years ago
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    \[6\sqrt{2}\]

  20. anonymous
    • 5 years ago
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    well no, that is 12, but you got that part right, your mistake was 3sqrt(2) * 1 i believe

  21. anonymous
    • 5 years ago
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    oh your right... i thought i was going to be able to eliminate the roots in the middle...

  22. anonymous
    • 5 years ago
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    you want to eliminate the roots on the bottom, that's why are we doing this. you don't have to eliminate the roots on the top.

  23. anonymous
    • 5 years ago
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    \[3-6\sqrt{2}+3\sqrt{2}\] -12 right?

  24. anonymous
    • 5 years ago
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    looks good for the top

  25. anonymous
    • 5 years ago
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    i kept getting 1-8

  26. anonymous
    • 5 years ago
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    looks good, so what's your end answer?

  27. anonymous
    • 5 years ago
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    hold on i haven't solved it yet, thought you were going to say i was wrong.

  28. anonymous
    • 5 years ago
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    where's your confidence? :)

  29. anonymous
    • 5 years ago
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    not in my math capabilities thats for sure haha. \[-9-3\sqrt{2}/-7\]

  30. anonymous
    • 5 years ago
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    okay so the numbers are right but my text book says all the nubmer are positive.

  31. anonymous
    • 5 years ago
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    looks good, don't forget parentheses if you write it like you typed it, and you can multiply by -1/-1 and get rid of all the negatives if you want

  32. anonymous
    • 5 years ago
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    parentheses? the ones used to foil? and okay thank you soo much your very helpful.

  33. anonymous
    • 5 years ago
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    i was just saying the way you typed your answer, could be -9 - (3sqrt(2)/-7) which is not the same thing

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