Aidez moi Svp c hyper important

bonjour

a) 1/2 ( x + 1/2)² - 1/2

= 1/2 ( x² + 2 x /2 + 1/4) - 1/2

= x²/2 + 2 x / 4 + 1/8 - 1/2

= 4 x²/ 8 + 4 x /8 + 1/8 - 4/8

= 4 x² + 4 x - 3/8  = second degré  

b )  x² - ( x + 1 )²

= x²- ( x² + 2 x +  1 )

= x² - x² + 2 x + 1

= 2 x + 1

c) ( x + 2/3) ( 3 x /2 - 1 )

  = 3 x²/2 - x + 6 x /6 - 2/3

= 9 x²/6 - 6 x / 6 + 6 x /6 - 4/6

= 9 x² - 4  =  second degré  

d)  ( x + 2/5 ) ( x -  2/5 )

= x² - 4/25  ( identité remarquable ) = second degré