Mathématiques

Question

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

1 Réponse

  • 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

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