bonjour,
a. 4 ( 2 - x ) + 5 = - 3 ( 2 x + 3 ) - 12
8 - 4 x + 5 = - 6 x - 9 - 12
- 4 x + 6 x = - 21 - 8 - 5
2 x = - 34
x = - 17
b. ( 3 x + 1 ) / 4 = ( 5 x - 2 ) / 5
( 15 x + 5 ) / 20 = ( 20 x - 8 ) /20
15 x + 5 = 20 x - 8
15 x - 20 x = - 8 - 5
- 5 x = - 13
x = 13/5
c. x /3 + 5/6 = 1/2 - x
2 x /6 + 5 /6 = 3/6 - 6 x / 6
2 x + 6 x = 3 - 5
8 x = - 2
x = - 2/8 = - 1/4
d . x - ( x + 1 ) = ( x + 3) - ( x - 3 )
x - x - 1 = x + 3 - x + 3
- x + x = 3 + 3 + 1
0 x = 7 pas de solution
