Réponse:
Périmètre = 2x + 3 + 2x + 4 + 2x + 2x + 3 + 3 + 2x + 4 + 2x + 2x + 2x + x + 2x + 2x + x + 5
= 10×2x + 3×3 + 2×4 + 2×x + 5
=10x + 9 + 8 + 5 + 2x
=10x + 2x + 22
= 12x + 22
voila
