General functional notation (e.g. f(x) ) is not supported. If you wish type a function such as f(x) = x^2, replace f(x) with y (or any other unused variable).

So, in your case, you nee to type the equation 'f(x)= 3x^5+2' as 'y = 3x^5+2' and select 'Solve for 'x'':

This way you will get the following solution:

Click here to see the solution in 'Algebrator'.