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Expanding Exponent Expressions

  • Thread starter thomas49th
  • Start date
  • #1
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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 :)
 

Answers and Replies

  • #2
458
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[tex]3x\sqrt{3x-1} \neq 12x^2 - 4x[/tex]
 
  • #3
655
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SORRY MY BAD I MENT [tex]2x\sqrt{3x-1}[/tex] = 12x^{2} - 4x

How do i get there?

Thanks :)
 
  • #4
458
0
[tex]2x\sqrt{3x-1} \neq 12x^2 - 4x[/tex]
 
  • #5
655
0
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:
  • #6
tiny-tim
Science Advisor
Homework Helper
25,789
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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]
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:
 
  • #7
655
0
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 :)
 

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