Mathématiques

Question

resoudre chaque equation

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


-2) -4(3 + x ) = 2x -6


-3) -3x +7 =3x - 11

2 Réponse

  • 2(x-5)= 3x +5
    2x -10= 3x +5
    2x -10 +10 -3x= 3x +5 +10 -3x
    x= 15

    -4(3+x)= 2x -6
    -12 -4x= 2x -6
    -12 -4x +12 -2x= 2x -6 +12 -2x
    -6x= 6
    -6x/-6= 6/-6
    x= -1

    -3x +7= 3x -11
    -3x +7 -7 -3x= 3x -11 -7 -3x
    -6x= -18
    -6x/-6=  -18/-6
    x= 3
  • 1) 2(x-5) = 3x + 5
    Développe: 2x + 10 = 3x + 5
    2x = 3x + 5 - 10
    2x - 3x = 5 - 10
    -x = -10
    x = 10

    2) -4 (3+x) = 2x -6
    -12 - 4x = 2x - 6
    -4x = 2x -6 +12
    -4x -2x = -6 + 12
    -6x = 6
    x = -1


    3) -3x + 7 = 3x -11
    -3x = 3x -11 -7
    -3x - 3x = -11 -7
    -6x = -18
    x = 3

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