Thực hiện phép tính a) 6x ( x + 3y – 1) – 6x^2 – 8xy b) ( x – 3)^2 – x^2 + 3x – 11 c) 2x – 25/ 4x – 20 + x + 10/ 4x -20 d)

1 bình luận về “Thực hiện phép tính a) 6x ( x + 3y – 1) – 6x^2 – 8xy b) ( x – 3)^2 – x^2 + 3x – 11 c) 2x – 25/ 4x – 20 + x + 10/ 4x -20 d)”

1. a) 6x ( x + 3y – 1) – 6x^2 – 8xy

   = 6x^2 + 18xy – 6x – 6x^2 – 8xy

   = 10xy -6x

   b) ( x – 3)^2 – x^2 + 3x – 11

   = x^2 – 6x + 9 – x^2 + 3x – 11

   = -3x – 2

   c) 2x – 25/ 4x – 20 + x + 10/ 4x -20

   = 2x – 25 + x + 10 / 4x – 20

   = 3x – 15 / 4x – 20

   = 3(x-5) / 4(x-5)

   = 3/4

   d) 3x/ x -2 – 6 / x +2 – 12x / x^2 – 4

   = 3x / (x-2)(x+2) – 6 / (x+2)(x-2) -12x / (x-2)(x+2)

   = 3x – 6 – 12x / (x-2)(x+2)

   = – 6 – 9x / (x-2)(x+2)

   = -3(2+x) / (x-2)(x+2)

   = -3/x-2

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