bonsoir
Ad = x + 3 + x - 2 = 2 x + 1
aire ABCD = ( 2 x + 1)² = 4 x² + 4 x + 1
aire ABEF = (x + 3) ( 2 x + 1) = 2 x² + x + 6 x + 3 = 2 x² + 7 x + 3
aire ECDF = 4 x² + 4 x + 1 - 2 x² - 7 x - 3 = 2 x² - 3 x - 2
2 x² + 7 x + 3 + 2 x² - 3 x - 2 = 4 x² + 4 x + 1