Question 129643: Okay, I'm trying to help my 13-year-old with Algebra. Some of it I remember, but I can't recall what to do with fractional exponents. The problem is:
(81)^-3/4. I have tried everything that I can think of, but to no avail. I don't know what to do with the negative sign when dealing with a negative fractional exponent. I know what to do with it when it's just a negative exponent, but the negative fractional exponent is throwing me.
Thanks,
Downs in Georgia
Answer by ptaylor(2198)   (Show Source):
You can put this solution on YOUR website! x^-n=1/x^n
So, 81 raised to the -3/4 power equals 1/81 raised to the 3/4 power and this equals the (4th root of 1/81)^3
4th root of 1/81=1/3 because 1/3*1/3*1/3*1/3=1/81
and (1/3)^3=1/27 because 1/3*1/3*1/3=1/27
Hope this helps--ptaylor
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