calcul litteral (qui peu me donner les reponse) merci a=6x-(5x+4) c=7(3x+4)-6 e=(3x-4)au carré b=(3xau carré-4)-(3x-2xau carré)-15 d=(x-4)(2x-5) f=(2x+5)(3x-1)+

a = 6x-(5x+4)
a = 6x -5x - 4 
a = x - 4

b = (3x² -4) - (3x-2x²) - 15
b = 3x² - 4 - 3x + 2x² - 15
b = 5x² - 3x - 19

c = 7(3x+4) - 6
c = 21x + 28 - 6
c = 21x + 22

d = (x-4)(2x-5)
d = 2x² - 8x - 5x + 20
d = 2x² - 13x + 20

e = (3x-4)² 
e = (3x-4)(3x-4)
e = 9x² - 12x - 12x + 16
e = 9x² - 24x + 16

f = (2x+5)(3x-1) + 5(x-2)
f = 6x² + 15x - 2x - 5 + 5x - 10
f = 6x² + 18x - 15

g = (3x-5)(2x+1) - (5x-1)(4x-3)
g = 6x² - 10x + 3x - 5 - ( 20x² - 4x - 15x + 3)
g = 6x² - 7x - 5 - 20x² + 19x - 3
g = - 14x² + 12x - 8