bonjour
x ( 2 x ) = 2 x ²
aire DCAB = 2 x ²
( 4 - 2 x ) ( 4 - x ) = 16 - 4 x - 8 x + 2 x² = 2 x² - 12 x + 16
aire HFCI = 2 x² - 12 x + 16
A = 2 x² + 2 x² - 12 x + 16 = 4 x² - 12 x + 16
4 x² - 12 x + 16 = 7
4 x² - 12 x + 16 - 7 = 0
4 x² - 12 x + 9 = 0
( 2 x - 3 )² = 0
x = 3/2
