Answer:
If you have a calculator with a "Y^X" function, you can raise 27 to the (1/3) power to get the cube root. Or, take the logarithm of 27, divide it by 3, and then find the anti log. That is, find the base 10 log of 27, divide it by three, and then compute 10 ^ that number. (Or of course you can use the base e log and raise e to the number.)
If you are willing to get into complex numbers, you can find that there are actually three cube roots of 27. One of them is 3. To find the other two, use de Moivre's formula (from Wikipedia):
If z is a complex number, written in polar form as
then the n nth roots of z are given by
where k varies over the integer values from 0 to n − 1.
This formula is also sometimes known as de Moivre's formula.
This leads to the two complex roots,
3 x ( (cos 120 degrees) + i x sin(120 degrees) ) and
3 x ( (cos 240 degrees) + i x sin(240 degrees) ).
These work out to be approximately:
3 x (-0.5 + i x 0.866) and
3 x (-0.5 - i x 0.866).
Explanation: