Bonjour et ce que vous pouvez m’aider à faire l’exercice 29, 30, 34 merci d’avance

Réponse :

29.

1. a. 3 - [12x(-5)] = 3 - (-60) = 63

b. - 7 - [14x(-5)] = -7 - (-70) = 63

30.

6a - 4 = - 1  

6a = 3

a = 3/6 = 1/2 = 0,5

9a + 6 = 13a + 14

9a - 13a = 14 - 6

- 4a = 8

a = -8/4 = -2

5 - 3a = 4a - 2

-3a - 4a = - 2 - 5

- 7a = - 7

a = 1

7a = 63

a = 63/7 = 9

4a + 9 = - 39

4a = - 39 - 9

4a = - 48

a = - 48/5 = - 12

31.

a. 6(3,5) + 3 = 4(3,5) - 3

21 + 3 = 14 - 3

24 = 11  NON

b. 6(-3) + 3 = 4(-3) -3

-18 + 3 = -12 - 3

-15 = -15   OUI

c. (6x0) + 3 = (4x0) - 3

0 + 3 = 0 - 3

3 = -3   non

32.

a. 2x = x + 1/2

2x - x = 1/2

x = 1/2    oui

b. 4t² = 4

t² = 4/4 = 1

t = 1    non

c. 3a + 1 = - 5a + 5

3a + 5a = 5 - 1

8a = 4

a = 4/8 = 2/4 = 1/2  oui

33.

Nadia

9 + 2x = - 15 - 4x

2x + 4x = - 15 - 9

6x = -24

x = - 24/6 = -4    oui

Gabriel

15 - 3t = - 1 + t

- 3t - t = - 1 - 15

- 4t = - 16

t = 16/4 = 4     non

34.

1. 3 + 13b = 8b - 7

13b - 8b = - 7 - 3

5b = - 10

b = - 2   oui

2. 16a - 20 = 26a

16a - 26a = 20

- 10a = 20

a = - 2   oui

3. 5,5x = 4x + 8

5,5x - 4x = 8

9,5x = 8

x = 8/9,5     non

4. 12,5y + 4 = 3y - 15

12,5y - 3y = - 15 - 4

15,5y = - 19

y = -19/15,5    non

5. 3x² - 6x - 24 = 0

3(-2)² - 6(-2) - 24 = 0

3(4) + 12 - 24 = 0

12 + 12 - 24 = 0    oui

6. 7/2t - 1 = 1/4t + 3                        7/2(-2) - 1 = 1/4(-2) + 3

7/2t - 1/4t = 3 + 1                              14/2 - 1 = 1/2 + 3

14/2t - 1/4t = 4                                  7 - 1 = 3,5

13/2t = 4                                           6 = 3,5         non

13/2(-2) = 4

- 26/2 = 4

-13 = 4    non

4.

5.

6.

Explications étape par étape