Mathématiques

Question

1.Calculer pour x= moins 2: A=2moins5x et B= moins 3 (4xmoins 2)
2.Calculer pour x= moins 4: C=(3+2x) (moins 2x+5) et D= moins 3x exposant 2+2xmoins 5
3.Calculer pour x= Fraction 3 sur 4 E=(3+2x)(moins x+2) et F= moins x exposant 2 + 2x moins 1


2 Réponse

  • Pour x = -2.
    A = 2 - 5 * (-2)
    A = 12
    B = -3 (4 * (-2) -2)
    B = -3 - 10
    B = 30

    Pour x = -4.
    C = (3 + 2 * (-4))(-2 * (-4) +5)
    C = -5 * 13
    C = -65
    D = -3 * (-4)² + 2 * (-4) - 5
    D = -48 - 13
    D = -61

    Pour x = 3/4
    E = (3 + 2 * 3/4) (-3/4 + 2)
    E = 9/2 * 5/4
    E = 45/8
    F = (-3/4)² + 2 * 3/4 -1
    F = 9/16 + 3/2 - 1
    F = 17/16


    Voilà !
  • 1)
    Pour x = -2.
    A = 2 - 5 * (-2)
    A = 2 - (-10)
    A = 12

    B = -3 (4 x (-2) -2)
    B = -3 (8 x -2)
    B = +3 x - 10
    B = 30

    2)
    Pour x = -4.

    C = (3 + 2 x (-4)) (-2 x (-4) +5)
    C = (3 - 8) (8 + 5)
    C = -5 x 13
    C = -65
    D = -3 * (-4)² + 2 * (-4) - 5
    D = -48 - 13
    D = -61

    3)
    Pour x = 3/4

    E = (3 + 2 x 3/4) (-3/4 + 2)
    E = (3 + 6/4) (5/4)
    E = (12/4 + 6/4) (5/4)
    E = (6/2 + 3/2) (5/4)
    E = 9/2 x 5/4
    E = 45/8

    F = (-3/4)² + 2 x 3/4 -1
    F = (-3/4)² + 6/4 -1
    F = (-3/4)² + 3/2 - 1
    F = 9/16 + 3/2 - 1
    F = 9/16 + 24/16 - 16/16
    F = 24/9 - 16/16
    F = 17/16

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