Bhaskara

There is currently a method called `bhaskara` that lives in `/lib/bhaskara.js`.
It is incomplete and needs to be fixed!

It expects 3 arguments: value of a, value of b, and value of c, and expects to return either a tuple [x, x'] or a single value if delta is 0.

### Acceptance Criteria:
1. Running `yarn test bhaskara` results in tests passing.
2. You have written a skeleton method for someone else to work on.
3. You have written tests surrounding your skeleton method.
4. Running `yarn lint` does not print any errors to the console!
5. Optional: write one or two more tests surrounding the method you are solving to account for potential edge cases.

### Please include the skeleton of a new method + an accompanying test for someone else to work on at the time of creating a pull request! A pull request will most likely be denied if it does not contain a skeleton method for someone else to work on! For more information, please read the [Contributing Guide](https://github.com/BlakeGuilloud/ganon/blob/master/CONTRIBUTING.md).

Thank you so much for your contribution!

Start by reading the incomplete method in lib/bhaskara.js and the existing tests selected by yarn test bhaskara. Use the stated three-argument behavior and acceptance criteria to define the expected cases, add the requested skeleton and accompanying tests, then confirm yarn test bhaskara and yarn lint pass.

Written by the indexing model from the issue text.