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8 x + 9 = 33

8 x  = 33 - 9

8 x =  24

x = 3

8 t - 10 = 5t - 2

8 t - 5 t = - 2 + 10

3 t = 8

t = 8/3

0 x = 5  donc pas de solution  

21 x- 15 = 4 x - 32

21 x - 4 x = - 32 + 15

17 x =    - 17

x = - 1

( 6 x + 5 ) ( 3 - 4 x ) =  - 8 x ( 3 x -  7)

18 x - 24 x² + 15 - 20 x = - 24 x² + 56 x

- 24 x² + 24 x² + 18 x - 20 x - 56 x =  - 15

- 58 x = - 15

x = 15/58

( 2 x - 7 ) / 5  = ( 5 - 8 x )  /3

6 x - 21 = 25 -  40 x

6 x + 40 x = 25 + 21

46 x =  46

x =  1

7 x /4 - 2 x /3 = 2 - 5 x / 6

21 x /12 -  8 x /12 = 24 /12 - 10 x /12

21 x - 8 x + 10 x = 24

23 x = 24

x = 24/23

x² = 81

x = √81 ou - √81

x = 9 ou ( - 9)

x² = - 64 ⇒ pas de solution dans  R

( 2 x + 5 )²  = 144

( 2 x + 5 )² - 144 = 0

( 2 x + 5 - 12 ) ( 2 x + 5 + 12 ) = 0

( 2 x - 7 ) ( 2 x + 17) = 0

x = 7/2 ou - 17/2

x² = 72

x = √72 ou - √72

x²  = 48

x = √48 ou - √48