Quadratic Minimizer Existence

Problem

For f(x) = a x^2 + b x + c, a finite minimizer exists only when a > 0, and then x* = -b / (2a).

Given a, b, and c, return the minimizer, or None when a <= 0.

Hint

A concave or linear objective diverges to -infinity.

case 1

in: [1,4,0]

expected: -2

case 2

in: [-1,2,0]

expected: null

case 3

in: [2,-8,3]

expected: 2

Starter codePython

def quadratic_minimizer_existence(a, b, c):
    # Your code here
    pass

3 test cases · run your code against them in the editor