bjr
aire carré = (2x+3)²
si x = 2
=> aire = (2*2 + 3)² = 7² = 49
aire rectangle 2
aire rectangle = x (x+12) puisque = longueur * largeur
si x = 2
alore rectangle = 2 (2+12) = 2*14 = 28 cm²
idem pour rectangle 3
somme aire figure 2 et 3 = aire figure 1
aire figure 1 = 4x² + 12x +9
aire figure 2 = x (x+12) =x² + 12x
aire figure 3 = (x² + 3) * 3 = 3x² + 9
et x² + 12x + 3x² + 9 = 4x² + 12x + 9 = aire figure 1
