Bonjour quelqu un peut m'aider s il vous plait

Bonjour,

1)

1- 7/4 x 2 - 1/6 + 2/-3

= 14/4 - 1/6 - 2/3

= (14 x 6) / (4 x 6) - (1 x 4) / (6 x 4)-  (2 x 8) / (3 x 8)

= 84/24 - 4/24 - 16/24

= 64/24

= (8 x 8) / (8 x 3)

= 8/3.

2- (7/4 - 2) + (- 1/6 - 2/- 3)

= [7/4 - (2 x 4) / (1 x 4)] + [- 1/6 + (2 x 2) / (3 x 2)]

= (7/4 - 8/4) + (- 1/6 + 4/6)

= - 1/4 + 3/6

= (- 1 x 6) / (4 x 6) + (3 x 4) / (6 x 4)

= - 6/24 + 12/24

= 6/24

= (6 x 1) / (6 x 4)

= 1/4.

2)

A = (2t - 4)² + 12

A = 4t² - 16t + 16 + 12

A = 4t² - 16t + 28

B = (1 + 2t)² - 20 (t - 1)  + 7

B = 1  + 4t² + 4t - 20t + 20 + 7

B = 4t² - 16t + 28

C = 4 (t - 3) (t - 1) + 16

C = (4t - 12) (t - 1) + 16

C = 4t² - 4t - 12t + 12 + 16

C = 4t² - 16t + 28.

A = B = C pour tout réel x.

Réponse :

Explications étape par étape

Bonjour

7/4 x 2 - 1/6 + 2/-3

= 14/4 - 1/6 - 2/3

= 42/12 - 2/12 - 8/12

= 42/12 - 10/12

= 32/12

= 8/3

(7/4 - 2) + (-1/6 - 2/-3)

= (7/4 - 8/4) + (-1/6 + 4/6)

= (-1/4) + 3/6

= (-3/12) + 6/12

= 3/12

= 1/4

Sont elles identiques :

A = (2t - 4)^2 + 12

A = 4t^2 - 16t + 16 + 12

A = 4t^2 - 16t + 28

B = (1 + 2t)^2 - 20(t - 1) + 7

B = 1 + 4t + 4t^2 - 20t + 20 + 7

B = 4t^2 - 16t + 28

C = 4(t - 3)(t - 1) + 16

C = 4(t^2 - t - 3t + 3) + 16

C = 4t^2 - 16t + 12 + 16

C = 4t^2 - 16t + 28

A = B = C