bonsoir
A = 2 x² - x - 3 x - 1
= 2 x² - 4 x - 1
B = 4 x² + 4 x + 1 + 3 x - 15
B = 4 x² + 7 x - 14
C = 4 x² - 1 - 4 x² + 4 x
= 4 x - 1
d = - 2 ( 25 + 20 x + 4 x² ) - ( 3 x - 6 x + 4 x - 8 )
= - 50 - 40 x - 8 x² - ( x - 8 )
= - 8 x² - 40 x - 50 - x + 8
= - 8 x² - 41 x - 42