bonjour
A = ( 3 x - 5)² - ( x - 6)( 3 x - 5)
1) A = 9 x² - 30 x + 25 - ( 3 x² - 5 x - 18 x + 30)
= 9 x² - 30 x + 25 - 3 x² + 5 x + 18 x - 30
= 6 x² - 7 x - 5
2) A = ( 3 x - 5) ( 3 x - 5 - x + 6)
= ( 3 x - 5) ( 2 x + 1)
3) pour x = - 4
A = ( - 12 - 5) ( - 8 + 1) = - 17 * - 7 = 119