Réponse :
bonjour,
( 2x -3 ) ( 3x -4 ) + 2 (2x -3)
=6x²-8x -9x +12 + 4x -6
= 6x² -17x +4x +6
=6x² -13x + 6
( 2x -3 ) ( 3x -4 ) + 2 (2x -3)
(2x -3) [ ( 3x -4 ) + 2 ]
(2x -3) ( 3x - 2 )
avec x = -2
6x² -13x + 6
=6×(-2)² - 13×(-2) +6
=6×4 +26 +6
=24+26+6
=56
(2x -3 ) (3x -2 ) = 0
2x - 3 = 0 ou 3x - 2 = 0
2x = 3 3x = 2
x = 3/2 x = 2/3
voila :)
