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newatthis

Multiply and simplify Radical Expression 1/2√5(1 1/2√20)

  • 10 months ago
  • 10 months ago

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  1. newatthis
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    |dw:1370239174862:dw|

    • 10 months ago
  2. newatthis
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    Hi I got the answer of 7/2√5 but when I do it I get something different.

    • 10 months ago
  3. yummydum
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    okay so lets write that a little prettier to deal with:\[{{1\over2}\sqrt{5}}\times{1~{1\over2}\sqrt{20}}~~\implies~~{{1\over2}\sqrt{5}}\times{{3\over2}\sqrt{20}}~~\implies~~{\sqrt{5}\over2}\times{3\sqrt{20}\over2}\]now that that looks a little better, let's solve:\[{{\sqrt{5}\times3\sqrt{20}}\over2}={3\sqrt{100}\over2}\]because 5 x 20 = 100\[3(10)\over2\]i think you've got it from here :)

    • 10 months ago
  4. yummydum
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    oh i meant to write \[3(10)\over4\]sorry

    • 10 months ago
  5. newatthis
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    I'm a bit lost I have to simplify this so would'nt 1 1/2√20 be 2 3/2√5

    • 10 months ago
  6. yummydum
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    \[1 {1\over2} = {3\over2}\]\[\sqrt{20}= 2\sqrt{5}\]\[{3\over2}\times{2\over1}\sqrt{5}~~=~~{3\over\cancel{2}}\times{\cancel{2}\over1}\sqrt{5}~~=~~\large3\sqrt{5}\]

    • 10 months ago
  7. newatthis
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    but the answer comes out to \[\frac{ 7 }{ 2 }\sqrt{5}\]

    • 10 months ago
  8. yummydum
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    and where are you getting this from?

    • 10 months ago
  9. newatthis
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    Our teacher placed the answer as \[\frac{ 7 }{ 2 }\sqrt{5}\]

    • 10 months ago
  10. newatthis
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    I didn't get this answer either this is why it's confusing

    • 10 months ago
  11. yummydum
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    1/2 times 3/2 = 3/4 sqrt 5 times sqrt 20 = sqrt100 = 10 3/4 times 10 = 7.5 i dont know what your teacher was doing, maybe you copied the question wrong

    • 10 months ago
  12. newatthis
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    No it's printed on my paper

    • 10 months ago
  13. yummydum
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    then im really not sure

    • 10 months ago
  14. newatthis
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    I appreciate your help Thank you yummydum

    • 10 months ago
  15. yummydum
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    no problem :)

    • 10 months ago
  16. newatthis
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    I got as my final answer \[\frac{ 3 }{ 4 }\sqrt{5} \] this is why it was confusing

    • 10 months ago
  17. newatthis
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    I had a person help me don't I don't believe it's correct here is why unless I'm wrong

    • 10 months ago
  18. saifoo.khan
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    Alright so i read the whole problem. Where are you stuck? We should get 15/2.

    • 10 months ago
  19. newatthis
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    \[1\frac{ 1 }{ 2 }\sqrt{20}\] would be \[\frac{ 3 }{ 2 }\] and \[\sqrt{20} would be 2\] add both \[2\frac{ 3 }{ 2 }\sqrt{5}\]

    • 10 months ago
  20. newatthis
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    teacher has an answer of \[\frac{ 7 }{ 2 }\sqrt{5}\] could the teacher be wrong

    • 10 months ago
  21. saifoo.khan
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    Yes. Teacher added the sqrt5 by misatke. Or maybe the question you wrote is incorrect.

    • 10 months ago
  22. newatthis
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    question is multiply and simplify \[\frac{ 1 }{ 2 }\sqrt{5}\left( 1\frac{ 1 }{ 2 } \sqrt{20}\right)\]

    • 10 months ago
  23. saifoo.khan
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    |dw:1370243682678:dw|

    • 10 months ago
  24. newatthis
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    Why is this so complicated? I'm lost

    • 10 months ago
  25. saifoo.khan
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    Which step is it that you don't understand?

    • 10 months ago
  26. newatthis
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    how would I multiply \[\frac{ \sqrt{5} }{ 2 }\times \frac{ 3*2 }{ 2 }\sqrt{5}\] I thought you multiply numbers not square roots with numbers

    • 10 months ago
  27. newatthis
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    my answer was \[\frac{ 3 }{ 4 }\sqrt{5}\] maybe this is wrong

    • 10 months ago
  28. saifoo.khan
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    |dw:1370244388921:dw|

    • 10 months ago
  29. newatthis
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    Wouldn't we keep the root? and just multiply getting \[\frac{ 15 }{ 2 }\sqrt{5}\]

    • 10 months ago
  30. saifoo.khan
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    No ma'am. Whenever it's given: sqrt3 * sqrt3 we will get "3" as answer. The roots cancel out leaving you with ONE three.

    • 10 months ago
  31. newatthis
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    This is how I started \[\frac{ 1 }{ 2 }\sqrt{5}(1\frac{1 }{ 2 }\sqrt{20})\] \[\frac{ 1 }{ 2 }\sqrt{5}(\frac{3 }{ 2 }\sqrt{5})\] \[\frac{ 1 }{ 2 }\times \frac{ 3 }{ 2 }=\frac{ 3 }{ 4 }\sqrt{5}\] I know this isn't corrected but I get this

    • 10 months ago
  32. saifoo.khan
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    How will you simplify sqrt 20?

    • 10 months ago
  33. newatthis
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    that's right it would be 4*5 which 4 goes down to 2 so it would be \[2\sqrt{5}\]

    • 10 months ago
  34. saifoo.khan
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    ^

    • 10 months ago
  35. newatthis
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    I forgot to add that \[\frac{ 1 }{ 2 }\sqrt{5}(2\frac{3 }{ 2 }\sqrt{5})\] it would be this correct and mix fractions to improper fractions would be \[2\frac{ 3 }{ 2 } would be \frac{ 7 }{ 2 }\] \[\frac{ 1 }{ 2 }\sqrt{5}(\frac{ 7 }{ 2 }\sqrt{5})\]

    • 10 months ago
  36. saifoo.khan
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    You made a mistake again. :P It's not 2 3/2

    • 10 months ago
  37. newatthis
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    so it's \[\frac{ 2 }{ 1 }X\frac{ 3 }{ 2 }\]

    • 10 months ago
  38. saifoo.khan
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    No. I think you should redo the problem. Show me yor steps please.

    • 10 months ago
  39. newatthis
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    ok

    • 10 months ago
  40. newatthis
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    \[\frac{ 1 }{ 2 }\sqrt{5}(1\frac{ 1 }{ 2 }\sqrt{20})\] \[\frac{ 1 }{ 2 }\sqrt{5}(\frac{ 3 }{ 2 } 2\sqrt{5})\] \[\frac{ 1 }{ 2 }\sqrt{5}(\frac{ 3 }{ 2 } 2\sqrt{5})\] at this point I'm lost

    • 10 months ago
  41. saifoo.khan
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    Awesome. No the 2's on right cancels out. Right?

    • 10 months ago
  42. newatthis
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    why would it cancel √20 would be 2√5 this is where I'm getting confused

    • 10 months ago
  43. newatthis
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    is 2 canceling with the other 2

    • 10 months ago
  44. saifoo.khan
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    sqrt(20) = sqrt(2*2*5) = 2 sqrt5 Agree?

    • 10 months ago
  45. newatthis
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    yes

    • 10 months ago
  46. saifoo.khan
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    Now the 2 from 2sqrt5 and the w in the denominator on the right canel out

    • 10 months ago
  47. newatthis
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    I'm with you on that

    • 10 months ago
  48. saifoo.khan
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    Right o what are we left with now?

    • 10 months ago
  49. newatthis
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    3√5

    • 10 months ago
  50. saifoo.khan
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    Right. And that is multiplied with..?

    • 10 months ago
  51. newatthis
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    \[\frac{ 1 }{ 2 }\sqrt{5}\]

    • 10 months ago
  52. saifoo.khan
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    Right now multiply it out.

    • 10 months ago
  53. newatthis
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    \[\frac{ 1 }{ 2 }\sqrt{5}\times \frac{ 3 }{ 1 }\sqrt{5}\] Is this looking correct?

    • 10 months ago
  54. saifoo.khan
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    yes

    • 10 months ago
  55. newatthis
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    \[\frac{ 3 }{ 2 }\sqrt{5}\]

    • 10 months ago
  56. newatthis
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    do I take of the √ and make it \[\frac{ 3 }{ 2 }\times \frac{ 5 }{ 1 }=\frac{ 15 }{ 2 }\]

    • 10 months ago
  57. saifoo.khan
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    Like a boss. (y)

    • 10 months ago
  58. newatthis
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    Thanks for everything wow :.)

    • 10 months ago
  59. help123please.
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    Good job helping @newatthis !!! @saifoo.khan

    • 10 months ago
  60. help123please.
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    Kudos to @yummydum too!

    • 10 months ago
  61. saifoo.khan
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    @yummydum is useless.

    • 10 months ago
  62. help123please.
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    No she isn't :p

    • 10 months ago
  63. help123please.
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    I'M useless.

    • 10 months ago
  64. help123please.
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    Yummydum isn't. Or you,for that matter.

    • 10 months ago
  65. newatthis
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    Thanks for everything it helps a lot when someone knows how to guide and explain it. :)

    • 10 months ago
  66. saifoo.khan
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    @help123please. believe me. I know her. @newatthis You're welcome. :)

    • 10 months ago
  67. help123please.
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    Well,yes...you've been here longer than me.

    • 10 months ago
  68. saifoo.khan
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    Lol. But no doubt she has a brown brain like me! D:

    • 10 months ago
  69. help123please.
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    O_O

    • 10 months ago
  70. help123please.
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    Yours is a great brain,Saif.

    • 10 months ago
  71. help123please.
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    U ARE 2 HELPFUL. Lol.

    • 10 months ago
  72. saifoo.khan
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    And it's brown too!

    • 10 months ago
  73. help123please.
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    Nope it's not.

    • 10 months ago
  74. saifoo.khan
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    I'm brown. Brain is brown too. Dummy is brown too. Hence she has a brown brain too.

    • 10 months ago
  75. help123please.
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    We're prolly weirding @newatthis out. Or at least,I am.

    • 10 months ago
  76. help123please.
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    :P

    • 10 months ago
  77. help123please.
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    'Hence,she has a brown brain too'. Hence. I like that word.

    • 10 months ago
  78. saifoo.khan
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    Lol.

    • 10 months ago
  79. newatthis
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    no I'm just doing math working my brain, or whatever is left. :)

    • 10 months ago
  80. help123please.
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    Saif,I just noticed your smartscore is mine,with the numbers flipped upside down. XD

    • 10 months ago
  81. saifoo.khan
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    Haha. Nice catch.

    • 10 months ago
  82. help123please.
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    IKR.

    • 10 months ago
  83. help123please.
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    *Flips PC upside down* OMGEE I HAVE A 99 SS!

    • 10 months ago
  84. saifoo.khan
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    Lol.

    • 10 months ago
  85. help123please.
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    98% of the time,when typing lol,you're not actually laughing. Did u know? :P

    • 10 months ago
  86. saifoo.khan
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    Make that 99%. I love laughing. It helps in exercising my face muscles. :P

    • 10 months ago
  87. help123please.
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    Lawl.

    • 10 months ago
  88. saifoo.khan
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    ;)

    • 10 months ago
  89. newatthis
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    so new question? \[2x \sqrt{7}(3x \sqrt{7})\] \[2x(3x)\sqrt{7}\sqrt{7}\] \[6x(\sqrt{49})\] Would this be correct?

    • 10 months ago
  90. newatthis
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    sorry I just threw this in here

    • 10 months ago
  91. help123please.
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    @newatthis please close this post and create a new thread.

    • 10 months ago
  92. yummydum
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    2x * 3x = 6x^2 not just 6x and √49 = 7 so now you have 6x^2 * 7 ....which is?

    • 10 months ago
  93. newatthis
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    \[42x ^{2}\]

    • 10 months ago
  94. yummydum
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    yes

    • 10 months ago
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