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 :)