When you are multiply any common x that has exponents, you only add the exponents and do not change the base number like shown below with x:, she should gave gotten:
[tex](1/2)^{2+1+3} = (1/2)^{6} = 1/64[/tex]
Here is the general example:
[tex]x^{n} + x^{n+1} = x^{2n+1}[/tex]