bonjour
A = ( x - 3)² - 3 x ( 2 x - 1)
= x² - 6 x + 9 - 6 x² + 3 x
= - 5 x² - 3 x + 9
B = ( 2 x - 1)² + ( 2 x + 1) ( 2 x - 1)
= 4 x² - 4 x + 1 + 4 x² - 2 x + 2 x - 1
= 8 x² - 4 x
C = 2 ( 2 x + 1/2) + ( x - 1/3)²
= 4 x + 1 + x² - 2 x/3 + 1/9
= 36 x + 9 + 36 x² - 6 x + 1
= 36 x² + 30 x + 10
D = ( x - 1) ( 2 x + 3) - ( x - 1/2)²
= 2 x² + 3 x - 2 x - 3 - ( x² - 2 x/2 + 1/4)
= 2 x² + x - 3 - x² + 2 x/2 + 1/4
= 8 x² + 4 x - 12 - 4 x² + 4 x + 1
= 4 x² + 8 x - 11
E = 9 x² - 6 x + 1 - ( 9 x² + 6 x + 1) + 9 x² - 36 x + 3 x - 1
E = 9 x² - 6 x + 1 - 9 x² - 6 x - 1 + 9 x² - 36 x + 3 x - 1
E = 9 x² - 45 x - 1