diff --git a/reed_solomon.py b/reed_solomon.py
index b2f1aba4e4f248f9a34e87ec2f8aba20e4675863..1427e9d5c581a8b47600e389390dda71e6621453 100644
--- a/reed_solomon.py
+++ b/reed_solomon.py
@@ -21,8 +21,21 @@ def get_possibilities(l: list):
 
 	return p
 
+# l : List of tuple (x, y)
 def lagrange_compute(l: list) -> polynome:
-	pass
+	# Produit de k = 0 > n
+	# bébé lagrange pour premier tuple choisit
+	from inverse_mult import inverse_mult
+
+	x = l[0][0]
+	coefs = []
+	for i, t in enumerate(l):
+		if(x != l[i][0]):
+			print(f"")
+			print(f"{t[0] * x} / inverse({x - t[0]} - 229)")
+			coefs.append(t[0] * inverse_mult(x - t[0], 229))
+	print(f"DEBUG {coefs}")
+	return polynome(coefs)
 
 def check_nb_error(l: list, p: polynome) -> int: