Bonjour il faut développer et réduire A = -2(3x + 4) + 4(5x - 3) B = (x - 5)-(-5x + 4) C = -(3x - 4) + (5x + 2) 3x D = (-x + 7)(1 - 3x) E = (4x + 2)(4x - 2) F

Bonjour,

A=-2(3x + 4) + 4(5x - 3)

 = -2×3x + 4×-2 + 4×5x -3×4

 = -6x -8 + 20x -12

 = 14x -20

B = (x - 5)-(-5x + 4)

  = x -5 +5x -4

  = 6x -9

C= -(3x - 4) + (5x + 2) 3x

  = -3x +4 + 5x×3x +2×3x

  = -3x +4 +15x² +6x

  = 15x² +3x +4

D = (-x + 7)(1 - 3x)

   = -x×1 -x×-3x +7×1 -3x×7

   = -x +3x² +7 -21x

   = 3x² -22x +7

E = (4x + 2)(4x - 2)

  = 4x×4x -2×4x +2×4x -2×2

  = 16x² -8x +8x-4

  = 16x² -4

F = 2(3 - x) - (5x - 2)(3x - 3)

  = 6−2x−(5x−2)(3x−3)

  = 6−2x−(15x² −15x −6x +6)

  = 6−2x−(15x² −21x +6)

  = 6−2x−15x² +21x −6

  = 6 + 19x −15x² −6

  = 19x−15x²

G = (y-2) (y + 2)

   = y×y + y×2 -2×y -2×2

   = y² + 2y -2y -4

   = y² −4

H = (5y - 8) (5y + 8)​

   = 5y×5y + 5y×8 -8×5y -8×8

   = 25y² + 40y -40y -64

   = 25y² -64

Voilà, bonne journée :)