You are right, you are giving a hint in the task section. Anyhow, although I believe that my suggestion(s) would improve the satisfaction of users trying the kata it's up to you if you want to make any more changes in this direction...

Sorry, I should have explained my reasoning:
In both the input ant the output section it is not clear if x starts at zero or one. Therefore I suggested to add the explanations within brackets.
I also added the last sentence because the description does not state how to format the string with the quadratic formula but e.g. 'x^2+8' and 'x^2+0x+8' represent the same quadratic formula but the second version would not pass the tests. Alternatively you could also explain the formatting of the string in the text...

Indeed, I had to read the tests as well to understand. However, I do not think that's bad if the tests are well-written. If you are working in an industry environment you might quite often get programming tasks defined mainly by tests instead of wordy documents...

I have suggestions to improve the description. Change the section "Input" to:

3 parameters representing the first 3 terms of a quadratic sequence (that means the outputs of the sequence for x = 1, x = 2 and x = 3, respectively).

Change the section "Output" to:

A tuple, with the quadratic formula (as a string) and the fourth and fifth term of the sequence (that means the outputs with x = 4 and x = 5, respectively).
Check the tests to understand how to format the quadratic formula considering e.g. different coefficients.

Nice improvements and additions!

Right, I guess at least a check to break the while loop if all board positions are taken but no player has won would be a good idea...

A hint that numbers above 999 should return "NaR" would be nice.