title: Python solve equation for one variable
body: <p>I'm trying to solve an equation in python using SymPy. I have a generated equation (something like <code>function = y(8.0-(y**3.0))</code> which I use with SymPy to create a new equation like this: <code>eq = sympy.Eq(function, 2)</code> which outputs <code>y(8.0-(y**3.0)) == 2</code>. but <code>sympy.solve(eq)</code> doesn't seem to work.</p>
  
  <pre><code>&gt;&gt;&gt; from sympy import Eq, Symbol as sym, solve
  &gt;&gt;&gt; y = sym('y')
  &gt;&gt;&gt; eqa = Eq(y(8.0-(y**3.0)), 8)
  &gt;&gt;&gt; solve(eqa)
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/usr/lib/pymodules/python2.6/sympy/solvers/solvers.py", line 332, in solve
      result = tsolve(f, *symbols)
    File "/usr/lib/pymodules/python2.6/sympy/solvers/solvers.py", line 716, in tsolve
      raise NotImplementedError("Unable to solve the equation.")
  NotImplementedError: Unable to solve the equation.
  </code></pre>
  
  <p>thanks for reading.</p>