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Réponse :

Bonjour

Explications étape par étape :

Exercice 1:

Développer et réduire les expressions suivantes :

A = 2(x + 5)

A = 2x +10

B = 3x (2x - 5)

B = 6x² -15x

C = 5x (3x - 4)

C = 15x² -20x

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

D = 3x +8x² -6x

D = -3x + 8x²

E = x - 4(x - 2)

E = x -4x +8

F = (2x + 3)(x + 6)

F = 2x² +12x +3x +18

F = 2x² + 15x + 18

G = (4x - 5)(3x - 1)

G = 12x² -4x -15x + 5

G = 12x² -19x +5

H = (2-x)(5 + x)

H = +10 +2x -5x -x²

H = -x² -3x +10

I = (3x + 1) (2x - 3)

I = 6x² -9x + 2x -3

I = 6x² -7x -3

Réponse:

Bonjour !!

A= 2(x+5)

= 2*x+2*5

= 2x+10 alors A= 2x + 10.

B= 3x(2x-5)

= 3x*2x - 3x*5

= 6x² - 15x alors B = 6x² - 15x.

C = 5x(3x - 4)

= 5x*3x - 5x*4

= 15x² - 20x alors C = 15x² - 20x.

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

= 3x + 2x*4x - 2x*3

= 3x + 8x² - 6x

= 3x - 6x + 8x²

= 8x² - 3x alors D = 8x² - 3x.

E = x - 4(x - 2 )

= x - 4*x + 4*2

= x - 4x + 8

= -3x + 8 alors E = -3x + 8.

F = (2x +3)(x + 6)

= 2x*x + 2x*6 + 3*x + 3*6

= 2x² + 12x + 3x + 18

= 2x² + 15x + 18 alors F = 2x² + 15x + 18 .

G = (4x-5)(3x-1)

= 12x² - 4x - 15x + 5

= 12x² - 19x +5 alors G = 12x² - 19x + 5.

H = (2-x)(5+x)

= 10 + 2x - 5x - x²

= -x² - 3x + 10 alors H = -x² - 3x + 10.

I = (3x+1)(2x-3)

= 6x² - 9x + 2x - 3

= 6x² - 7x - 3 alors I = 6x² - 7x - 3.

Merci.