combinning radicals of different nth powers

[reggedude]

without using rational exponents how would you combine, say the square root of x and the cube root of x
(sorry i do not know how to insert the proper math char.)

 

[pka]

without using rational exponents how would you combine, say the square root of x and the cube root of x.

Why would anyone want to do that?

 

[reggedude]

I just would like to see if and how it would be done in order to then prove that using rational exponents would be be advantagious.