Sagot :
bonjour
A = 12 x + 21 + 8 x² - 36 x = 8 x² - 24 x + 21
b = 14 x² - 35 x - 2 x² + 5 x = 12 x² - 30 x
C = 6 x² - 4 x - 15 x + 10 = 6 x² - 19 x + 10
D = 3 x - 2 x² + 21 - 14 x + 20 x² + 5 x - 8 x - 2
d = 18 x² - 14 x + 19
Réponse :
bonjour
A= 3(4x + 7) + 4 x (2x - 9)
= 12x + 21 + 8x² - 36x
= 8x² - 24x + 21
B= 7x(2x - 5) - x(2x - 5)
= 14x²- 35x - 2x² + 5x
= 12x² - 30x
C= (2x - 5)(3x - 2)
= 6x² - 4x - 15x + 10
= 6x² - 19x + 10
D= (x + 7)(3 - 2x) + (5x - 2)(4x + 1)
= 3x - 2x² + 21 - 14x + 20x² + 5x - 8x - 2
= 18x²-14x + 19
voila :)