## Exercice 1 — Échauffement : print ou return ?

def f(x):
    return x**2 + 3*x - 1

def g(x):
    print(x**2 + 3*x - 1)

from math import sqrt

def discriminant(a, b, c):
    delta = b**2 - 4 * a * c
    return delta

def solutions(a, b, c):
    delta = discriminant(a, b, c)
    if delta > 0:
        x1 = (-b - sqrt(delta)) / (2 * a)
        x2 = (-b + sqrt(delta)) / (2 * a)
        return [x1, x2]
    elif delta == 0:
        x0 = -b / (2 * a)
        return [x0]
    else:
        return []

## Exercice 2 — factorielle

## Exercice 3 — somme_carres

## Exercice 4 — suite_u

#### Mini-projet : calendrier

## Exercice 5 — bissextile

## Exercice 6 — nb_jours_annee

## Exercice 7 — nb_jours_mois

## Exercice 8 — nb_jours_ecoules

## Exercice 9 — difference_de_jours

## Exercice 10 — date

## Exercice 11 — jour_de_la_semaine

## Exercice 12 — prochain_vendredi_13