Réponse:
bsr
Explications étape par étape:
A= (2x-3)(7-x)
A= 14x -2x^2 -21 + 3x
A= - 2x^2 +17x -21
B=(x+y)(2x-y)
B= 2x^2 -xy +2xy - y^2
B= 2x^2 - y^2 +xy
C= (x-7)(2+y)
C= 2x + xy - 14 -7y
C = 2x -7y + xy - 14
D = (x - 1)(1 - x)
D = x - x^2 - 1 + x
D = - x^2 + 2x - 1
E= 3 (3a + 4)^2
E = 3 ( 9a^2 + 24 a + 16)
E = 27 a^2 + 72a + 48
F= -5 (4-b)^2
F = -5 ( 16 - 8b + b^2)
F = - 80 + 40b - 5b^2
F = -5b^2 + 40b - 80
