Répondre :
bonsoir
P = 2 ( x + 2 x + 5 ) = 2 x + 4 x + 10 = 6 x + 10
6 x + 10 = 31
6 x = 31 - 10
6 x = 21
x = 21 /6 = 3.5
longueur = 2 x + 5 = 2 * 3.5 + 5 = 12
largeur = 3.5
bonne soirée
bonsoir
P = 2 ( x + 2 x + 5 ) = 2 x + 4 x + 10 = 6 x + 10
6 x + 10 = 31
6 x = 31 - 10
6 x = 21
x = 21 /6 = 3.5
longueur = 2 x + 5 = 2 * 3.5 + 5 = 12
largeur = 3.5
bonne soirée