Bonjour pourriez-vous m’aider svp équations merci

Bonjour,

6) 9x - 7x + 5 - 9x = 6 - 4x + 8x

9x - 9x - 7x + - 8x + 4x = 6 - 5

- 11x = 1

x = 1/11

7) 8/7x = 14

8/7x = 98/7

8x = 98

x = 98/8

x = 12,25

8) 6 (3y - 5) = - (- 5 - y)

18y - 30 = 5 + y

18y - y = 5 + 30

17y = 35

y = 35/17

9) 12t = 48

t = 48/12

t = 4

10) 7x - 2x + 2x - 9 + 7x = 14x

- 2x + 2x + 7x + 7x - 14x = 9

0x = 9 --> Impossible

11) x/2 = 25

12) - (18 - x) + 7 (3x + 5) = - (2 - 4x)