bonjour je ne comprends pas les equations avec fractions de l'exercices 1 . le voila ce dm :http://www.scolinfo.net/Scolinfo/cahiertexte/devoir/9/49/3880/2012_2013%20DM7%20Probl%C3%A8mes%20sur%20les%20%C3%A9quations.pdf

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2013-01-02T19:19:58+01:00

a) 7x+5 =5x-21

= 7x-5x = -21-5

= 2x= -26 d'où x = -13

 

b) 5x-2(2x+3) = 1-5(x-1)

= 5x-4x-6 = 1-5x+5

= 5x-4x+5x = 1+5+6

= 6x= 12  x = 12/6 = 2

 

c) (x+1)/3 = x+2

= (x+1)/3 = (3x+6)/3

= x-3x =6-1

-2x =x5  x = -5/2

 

d) (x-10)/5 -(12-x)/10 = (x-2)/10

= (2x -20)/10 -(12-x)/10 = (x-2)/10

=2x +x-x = -2+12+10

= 2x = 20 donc x = 10

 

e) (x/3)-4 = (2x-1)/2

= (2x/6)-(24/6) = (6x-3)/6

= 2x -6x = -3+24

= -4x = 27 donc x = -27/4