bonjour
A = ( 2 x - 7 ) ( 3 x + 2 ) - ( 4 x - 8 ) ( 3 x + 2 )
1. A = 6 x² + 4 x - 21 x - 14 - ( 12 x² + 8 x - 24 x - 16 )
= 6 x² - 17 x - 14 - 12 x² - 8 x + 24 x + 16
= - 6 x² - x + 2
2. A = ( 3 x + 2 ) ( 2 x - 7 - 4 x + 8 )
= ( 3 x + 2 ) ( - 2 x + 1 )
3. pour x = - 5
A = ( - 15 + 2 ) ( - 2 - 5 )
= - 13 * - 7 = 91
pour x = - 2/3
A = ( - 6/3 + 2 ) ( 4/3 + 1 )
= ( - 6 /3 + 6/3) ( 4/3 + 3/3)
= 0