Bonjour

1) A = 3x + 4x (2x + 5)

A = 3x + 8x² + 20x

A = 8x² + 23x

2) B = (2x - 7) (- 3x + 7)

B = - 6x² + 14x + 21x - 49

B = - 6x² + 35x - 49

3) C = (4x + 5) (2x + 6)

C = 8x² + 24x + 10x + 30

C = 8x² + 34x + 30

4) D = (- 3 + x) (- 2x - 5)

D = 6x + 15 - 2x² - 5x

D = - 2x² + x + 15

5) E = (x + 7) (3 - 2x) + (5x - 2) (4x + 1)

E = 3x - 2x² + 21 - 14x + 20x² + 5x - 8x - 2

E = - 2x² + 20x² + 3x + 5x - 14x - 8x + 21 - 2

E = 18x² - 14x + 19

6) F = (5x + 4) (2x + 3) - (5x + 7)

F = 10x² + 15x + 8x + 12 - 5x + 7

F = 10x² + 15x + 8x - 5x + 12 + 7

F = 10x² + 18x + 19

7) G = (5x - 7)² + (4x - 8) (4x + 8)

G = 25x² - 70x + 49 + 16x² - 64

G = 25x² + 16x² - 70x + 49 - 64

G = 41x² - 70x - 15.