Mathématiques

Question

Résoudre les équations:

2x + 5 = 15 - 3x
-6x + 4 = -1 - x
7m + 10 = m - 8
-12y = 4 - 13y
4x = 36
18 = -4a
4 cinquième m = 2 tiers

2 Réponse

  • a  x= 2
    b  x =1
    c  m  =- 1/3
    d  y = 4
    e  x = 9
    f  -9/2 = a
    g  m = 5/6

  • 1 ) 2x + 5 = 15 -3x

    2x +3x = 15-5

    5x        = 10

       x       = 10/5

       x        = 2

    2) -6x +4 = -1-x

        -6x +x   = -4 -1

             -5x   =  -5

               x      = -5/(-5)

                x      = 1

    3) 7m +10 = m-8

         7m -m  = -10 -8

              6m  = -18

                m =     -18/6

                m =  - 3

    4) -12y = 4 -13y

       -12y +13y = 4

                 1y   = 4

                   y = 4

    5) 4x = 36

         x = 34/4

          x= 9

    6) 18 = -4a

        18/(-4) = a

         a = -4.5

    7 ) 4/5m = 2/3

             m =  2/3  /  4/5

             m =   2/3 x 5/4  

            m   =  10 / 12

            m =  5/6


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