bonjour
A = 9 x² + 30 x + 25
B = x² - 16
C = x² - 8 x + 16 + x² + 4 x + 4 = 2 x² - 4 x + 20
D = ( x + 5 + 2 x - 4 ) ( x + 5 - 2 x + 4 ) = ( 3 x + 1 ) ( - x + 9 )
