$\text{Rút gọn các biểu thức sau:}$ $\text{a)}$ $A= (4x-1)(3x+1)-5x(x-3)-(x-4)(x-3)$ $\text{b)}$ $A= (5x-2)(x+1)-3x(x^{2} -x-3)-2x(x-5)(x-4)$

0 bình luận về “$\text{Rút gọn các biểu thức sau:}$ $\text{a)}$ $A= (4x-1)(3x+1)-5x(x-3)-(x-4)(x-3)$ $\text{b)}$ $A= (5x-2)(x+1)-3x(x^{2} -x-3)-2x(x-5)(x-4)$”

1. `a) A = (4x−1) (3x+1)− 5x (x−3) − (x−4) (x−3)`

   `A = 12x^2 + 4x – 3x – 1 – 5x^2 + 15x – x^2 + 3x + 4x – 12`

   `A = 6x^2 + 23x – 13`

   `b) A = (5x−2) (x+1)−3x (x^2−x−3)−2x (x−5) (x−4)`

   `A = 5x^2 + 5x – 2x – 2 – 3x^3 + 3x^2 + 9x – 2x( x^2 – 4x – 5x + 20 )`

   `A = 8x^2 + 2x – 2 – 2x^3 + 8x + 10x^2 + 40x`

   `A = -2x^3 + 18x^2 + 50x – 2`

    

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2. $\text{Rút gọn các biểu thức sau:}$

   $\text{a)}$ $A= (4x-1)(3x+1)-5x(x-3)-(x-4)(x-3)$

                      $A = (12x² + 4x – 3x – 1) -5x² + 15x – (x² – 3x – 4x + 12)$

                      $A = 12x² + x – 1 – 5x² + 15x – x² + 7x – 12$

                      $A = 6x² + 23x – 13$

   $\text{b)}$  $B = (5x – 2).(x + 1) -3x.(x² – x – 3) -2x.(x – 5).(x – 4)$

                      $B = 5x² + 5x – 2x – 2 – 3x³ + 9x + (-2x² + 10x)×(x – 4)$

                      $B = 5x² + 5x – 2x – 2 – 3x³ + 9x – 2x³ + 8x² + 10x² – 40x$

                      $B = -5x³ + 26x² – 28x – 2$

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