bonjour
A = ( 2 x - 3) ( 4 x - 1)
A = 8 x² - 2 x - 12 x + 3 = 8 x² - 14 x + 3
pour x = 1.5 A = 18 - 21 + 3 = 0
B = ( 2 x - 3)² + ( 2 x - 7) ( 6 x - 9)
B = 4 x² - 12 x + 9 + 12 x² - 18 x - 42 x + 63
= 16 x² - 72 x + 72
pour x = 1.5 B = 36 - 108 + 72 = 0
D = x² + 10 x + 25 - ( 3 x + 4)²
a) D = x² + 10 x + 25 - ( 9 x² + 24 x + 16)
= x² + 10 x + 25 - 9 x² - 24 x - 16
= - 8 x² - 10 x + 9
b) x² + 10 x + 25 = ( x + 5)²
c) D = ( x + 5)² - ( 3 x + 4)²
= ( x + 5 + 3 x + 4) ( x + 2 - 3 x - 4)
= ( 4 x + 9) ( - 2 x - 2 )