Réponse:
A = - 6x² - 31x - 14 = - ( 2x + 1 ) ( 3x + 14 )
B = - 5x² + 15x + 8 = - 5 ( x - ( - √385/10 + 3/2 )) ( x - ( √385/10 + 3/2 ))
C = 8x² + 18x - 11 = ( 2x - 2 ) ( 4x + 11 )
D = - 7x² - 2x + 5 = ( 5 - 7x ) ( x + 1 )
E = 3x² - 3x - 6 = 3 ( x - 2 ) ( x + 1 )