Réponses

2014-05-11T10:21:19+02:00
A) 1/21x +2 = 4/21-4 
1/21x = 4/21 - 4 - 2
1/21x = 4/21 - 6
1/21x = -122/21
x = (-122/21) / (1/21) or diviser par un nombre c'est multiplier par son inverse 
x = (-122/21)*(21/1)
x = -2562/21
x = -122

b). x/6 +1 =5/6x -1/6
x/6 - 5/6x = -1/6 - 1
-2/3x = -7/6
x = (-7/6) / (-2/3)
x = (-7/6)* (3/-2)
x = -21/-12
x = 7/4
 
c) 2/3x+2=4/9x-1 
2/3x - 4/9x = -1 -2
-13/9x = -3
x = -3 / (-13/9)
x = -3 * (9/-13)
x = 27/13

d) 6/5x -21/10=27/10x-3/5 
6/5x - 27/10x = -3/5 + 21/10
-3/2x = 3/2
x = (3/2) / (-3/2)
x = (3/2)*(2/-3)
x = 6/-6 = -1 

e ) 3/2x+2 =2/3x -1
3/2x - 2/3x = -1 - 2
5/6x = -3 
x = -3 / (5/6)
x = -3 * (6/5)
x = -18/5