Question 648923
By definition, {{{y = root(3,x)}}} just means that {{{y^3 = x}}}.

So, say I ask you what the cube root of 216 is.  

Let's go through our list of cubes.

2^3 = 8
3^3 = 27
4^3 = 64
5^3 = 125
6^3 = 216
7^3 = 243
etc..

Since 6^3 = 216, then  {{{root(3,216) = root(3,6^3) = 6}}}