1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Expanding Exponent Expressions

  1. Apr 12, 2008 #1
    Hi, I don know how to go about expanding things such as

    [tex]3x\sqrt{3x-1}[/tex]
    apparently that equals 12x^{2} - 4x

    i know that [tex]3x\sqrt{3x-1}[/tex] can be written as [tex]3x(3x-1)^{\frac{1}{2}}[/tex]

    but i dont know what to do. I cant remeber.

    Thanks :)
     
  2. jcsd
  3. Apr 12, 2008 #2
    [tex]3x\sqrt{3x-1} \neq 12x^2 - 4x[/tex]
     
  4. Apr 12, 2008 #3
    SORRY MY BAD I MENT [tex]2x\sqrt{3x-1}[/tex] = 12x^{2} - 4x

    How do i get there?

    Thanks :)
     
  5. Apr 12, 2008 #4
    [tex]2x\sqrt{3x-1} \neq 12x^2 - 4x[/tex]
     
  6. Apr 13, 2008 #5
    SORRY. Ill start a bit further back
    i have this:

    [tex]x^{2}\frac{3}{2}(2x-1)^{-1}{2} + 2x\sqrt{3x-1}[/tex]

    and I dont know how it simplifies to

    [tex]\frac{3x^{2} + 12x^{2} - 4x}{2\sqrt{3x-1}}[/tex]


    I cant see that the
    [tex]x^{2} x \frac{3}{2}(2x-1)^{-\frac{1}{2}} [/tex] will equal [tex]\frac{3x^{2}}{2\sqrt{3x-1}}[/tex]

    but i cant see how the other bit simplifies... can you show me

    Thanks
     
    Last edited: Apr 13, 2008
  7. Apr 13, 2008 #6

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Hi thomas49th! :smile:

    Do you follow:
    [tex]\frac{3x^{2}}{2\sqrt{3x-1}}\,+\,2x\sqrt{3x-1}[/tex]

    [tex]= \frac{3x^{2}}{2\sqrt{3x-1}}\,+\,\frac{2x(3x-1)}{\sqrt{3x-1}}[/tex] ? :smile:
     
  8. Apr 13, 2008 #7
    yes i can see a common denomitor so u multiply both the numerator and demonitor by [tex]2\sqrt{3x-1}[/tex] of the fraction
    Cheerz :)
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook