Réponse :
Explications étape par étape
E= 4x²-16 identité remarquable a² - b² = ( a - b ) ( a + b )
⇔ E = ( 2x - 4 ) ( 2x + 4 )
F = 81 - 16 x² + ( 9 - 4x ) ( 2x + 1 )
⇔ F = ( 9 - 4x ) [ ( 9 + 4x ) + ( 2x + 1 ) ]
B = ( 1 - 2x )² + 6x
⇔ B = 1 - 4x + 4x² + 6x
⇔ B = 4x² + 2x + 1
C = -6 ( 2 + 5x ) - ( 3+x )²
⇔ C = -12 - 30x - ( 9 + 6x + x² )
⇔ C = - 12 - 30x - 9 - 6x - x²
⇔ C = - x² - 36x - 21
G = 6x / 2x + 1 + 8
⇔ G = (6x / 2x) + 9
⇔ G = 3 + 9 = 12
H = 2/ 3x-1 + 5 / x
⇔ H = ( 17x - 5 ) / x (3x-1)
⇔ H = 17x - 5 / 3x²- x
