import math
def solve(a=0,b=0,c=0):
    if a==0 and b==0 and c==0:
        return ['all']
    elif a == 0 and b == 0:
        return []
    elif a==0:
        return [(c*(-1))/b]
    elif b==0:
        return [math.sqrt((-1*b)/a)]
    elif  c==0:
        return[0, (-1*b)/a]
    else:
        q = b**2
        w = -4*a*c
        D = q+w
        if D<0:
            return[]
        elif D== 0:
            return[(-1*b)/(2*a)]
        else:
            D = math.sqrt(D)
            return[int(((-1*b)-D)/(2*a)), ((-1*b)+D)/(2*a) ]