You can use the Goal Seek to find the input value (for a given function) that results in a certain function result/output (goal).
This code involves of root finding methods; at a first step, via the Line Search method, and, at the second step, the Bisection method.
This tool requires that NumPy be installed.
Please see ExampleScript.py
You are free to use, modify and distribute the code as long as authorship is properly acknowledged.