Why I got NaN

Question

Sometimes I got NaN as output when I enter some random numbers like 5, 4, 6
Code link:-
https://replit.com/@Girish-kumarku5/Quadratic-equation-solver?s=app

Answer 1

A negative number is produced at line 9 when all 3 inputs are positive numbers

Math.sqrt() will return null when a negative number is passed.

Null is not a number.

btw
The link seems to be broken when using the android app.

Answer 2

I fixed the code