Bonsoir,

1)-3=x+3  

x + 3 = - 3

x = - 3 - 3

x = - 6

2) −3x+1=−5x−9

-3x + 5x = - 9 - 1

2x = - 10

x = - 10/2

x = - 5

3) 6x=−36

x = 36/6

x = 6

4) 2=​x​​/3​​

x/3 = 2

x/3 = 6/3

x = 6

5) v² =25

v = √25

v = 5

6) −(−6x−2)−x=3(−6x−3)−2

+ 6x + 2 - x = - 18x - 9 - 2

6x + 18x - x = - 9 - 2 - 2

23x = - 13

x = - 13/23

7) -6x + 2 = -10

- 6x = - 10 - 2

- 6x = - 12

x = 12/6

x = 2

8) −18n−8n​²+(6+2n)(4n−1)=0

- 18n - 8n² + 24n - 6 + 8n²- 2n = 0

- 8n² + 8n² - 18n - 2n + 24n = 6

4n = 6

n = 6/4

n = 3/2

9) ​2​​/3​​=​x​​/7​​

x/7 = 2/3

3x/21 = 14/21

3x = 14

x = 14/3

10) ​ −6(6+6x)−3x=6(​6​​/3​​−2x)

- 36 - 36x - 3x = 36/3 - 12x

- 36x - 3x + 12x = 12 + 36

- 27x = 48

x = 48/27

x = 16/9

11) ​6​​/--5 =​6​​/--5 +8x   --> Erreur de signes --

12) {​7h+3k=62​

{7h+2k=53​

- 14h - 6k = - 124

21h + 6k = 159

7h = 35

h = 35/7

h = 5

7h + 2k = 53

7 * 5 + 2k = 53

35 + 2k = 53

2k = 53 - 35

2k = 18

k = 18/2

k = 9

S = (5 ; 9)

• ex5) v²=25 donc v= + ou- V25 soit +5 ou -5 (2 solutions).