Bonjour,

6)

A = x - 3x² + 6x - 10 + 7x²

A = - 3x² + 7x² + x + 6x - 10

A = 4x² + 7x - 10

B = 9x - x² + 3 - 10x + 2x² - 5

B = - x² + 2x² + 9x - 10x + 3 - 5

B = x² - x - 2

C = 3 + x - 4x² + 5x² - x - 10

C = - 4x² + 5x² + x - x + 3 - 10

C = x² - 7

D = - x - 3x² + 5x - 8 + 6 + 2x

D = - 3x² - x + 5x + 2x - 8 + 6

D = - 3x² + 6x - 2.

7)

A = 2 + 6 (x + 8)

A = 2 + 6x + 48

A = 6x + 50

B = 2 (3x + 10) + 30

B = 6x + 20 + 30

B = 6x + 50

Donc : A = B.