def racines(coef):
    a, b, c, delta = coef[0], coef[1], coef[2], b*b-4*a*c
    if delta<0:
        result = 0
    else:
        if delta == 0:
            result = 1, -b/(2*a)
        else:
            result = 2, (-b-delta**0.5)/(2*a), (-b+delta**0.5)/(2*a)
    return result