def F(a, b, c):
    d = b**2 - 4 * a * c;
    import math
    if d > 0:
        x1 = (-b + math.sqrt(d)) / (2 * a)
        x2 = (-b - math.sqrt(d)) / (2 * a)
        return(x1,x2)
    if d == 0:
    	x = -b / (2 * a)
    	return(x)
    if d<0:
        x1 = complex(-b/2, ((-d)**(1/2))/ 2)
        x2 = complex(-b/2, -((-d)**(1/2))/ 2)
        return(x1,x2)
print(F(5,-9,-2))
print(F(20,5,40))
print(F(2,4,2))