bonjour
1. A = ( a - 3 )( a + 6 ) = a² + 6 a - 3 a - 18 = a² + 3 a - 18
2. B = [( 2 a - 4 ) ( a + 9 ) ] / 2
B = ( 2 a² + 18 a - 4 a - 36 ) / 2
B = ( 2 a² + 14 a - 36 ) /2 = a² + 7 a - 18
3. a² + 7a - 18 - ( a² + 3 a- 18 )
= a² + 7 a - 18 - a² - 3a + 18
= 4 a
B a la plus grande aire
