SOLUTION: root of -8 / x, the problem has a little 3 in front of the root sign. I need to rationalize the denominator.

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Question 291141: root of -8 / x, the problem has a little 3 in front of the root sign. I need to rationalize the denominator.
Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!
root of -8 / x, the problem has a little 3 in front of the root sign. I need to rationalize the denominator.


root%283%2C-8%2Fx%29
First we can always take a negative out of a radical if the
index of the radical is odd. The index is 3 (That's the
little 3 in front of the root sign) and therefore odd. So
let's take the negative sign outside:
-root%283%2C8%2Fx%29
So we need to get an exponent of 3 in the denominator. There is
an x there, but we need there to be an x%5E3 there, so
we multiply top and bottom by x%2Ax
-root%283%2C%288%2Ax%2Ax%29%2F%28x%2Ax%2Ax%29%29
-root%283%2C%288%2Ax%5E2%29%2F%28x%5E3%29%29
Now we use the principle "The cube root of a quotient equals
the quotient of cube roots".
-root%283%2C8%2Ax%5E2%29%2Froot%283%2Cx%5E3%29
The denominator is now the cube root of a cube, so
that takes away the radical and the exponent, and just
leaves x in the bottom.
-root%283%2C8%2Ax%5E2%29%2Fx
Only one thing left to do, and that is to take the
cube root of 8 which is 2, and put 2 on the outside
of the cube root:
-%282root%283%2Cx%5E2%29%29%2Fx