what is 9^5/2 simplified

If you mean  $${{\mathtt{9}}}^{\left({\frac{{\mathtt{5}}}{{\mathtt{2}}}}\right)}$$ ,you can write the expression as  $${\sqrt{{{\mathtt{9}}}^{{\mathtt{5}}}}}$$ which is  $${\sqrt{{\mathtt{59\,049}}}}$$  which is  $${\mathtt{243}}$$ .

If you mean  $${\frac{{{\mathtt{9}}}^{{\mathtt{5}}}}{{\mathtt{2}}}}$$ ,you can write the expression as  $${\frac{{\mathtt{59\,049}}}{{\mathtt{2}}}}$$  which is  $${\mathtt{29\,524.5}}$$ .

It's already in its simplest form. If you want to write it in another way though you could express it as sqrt(9^5)

Thanks Gibson and Brodude,

A little 'trick' here 

$$9^{5/2} = (9^{1/2})^5 =(\sqrt9)^5=3^5=243$$

If you are good with numbers you can do that in your head :)