SOLUTION: 9y 2/3 - 24y 1/3 + 16. I'm so lost when it comes to this stuff!!!

Algebra ->  Square-cubic-other-roots -> SOLUTION: 9y 2/3 - 24y 1/3 + 16. I'm so lost when it comes to this stuff!!!      Log On


   

Question 21652: 9y 2/3 - 24y 1/3 + 16.
I'm so lost when it comes to this stuff!!!
Answer by longjonsilver(2297) About Me  (Show Source):
You can put this solution on YOUR website!
what about it?

9y%5E%282%2F3%29+-+24y%5E%281%2F3%29+%2B+16

First, lets change variable to remove the fractional part of the powers... like so:

Let x = y%5E%281%2F3%29, so that x%5E2+=+y%5E%282%2F3%29}. We therefore get:

9x%5E2+-+24x+%2B+16 which is a straight forward quadratic now, which hopefully can be factorised:


9x%5E2+-+24x+%2B+16
(3x - 4)(3x - 4)
ie %283x+-+4%29%5E2

So, writing this back into the original variable, y, we have %283y%5E%281%2F3%29+-+4%29%5E2

Hope this is clear?

jon.