bonjour
A(x) = (2 x - 3) (5 x - 4)
A (x) = 10 x² - 8 x - 15 x + 12
A (x) = 10 x² - 23 x + 12
B(x) = 2 x (5 x - 3) -7
B (x) = 10 x² - 6 x - 7
C(x) = 3 x - (x - 1) - (x + 7) (x + 3)
C (x) = 3 x - x + 1 - ( x² + 3 x + 7 x + 21 )
C (x) = 2 x + 1 - x² - 3 x - 10 x - 21
C (x) = - x² - 11 x - 20
