(7x-8)(7x+8)-10(2x+3)^2+5x(3x-2)^2-4x(x-5)^2 (x^2-3)(x^2+3)-5x^2(x+1)^2-(x^2-3x)(x^2-2x)+4x(x+2)^2

0 bình luận về “(7x-8)(7x+8)-10(2x+3)^2+5x(3x-2)^2-4x(x-5)^2 (x^2-3)(x^2+3)-5x^2(x+1)^2-(x^2-3x)(x^2-2x)+4x(x+2)^2”

1. Đáp án: + Giải thích các bước giải:

   `(7x-8)(7x+8)-10(2x+3)^2+5x(3x-2)^2-4x(x-5)^2` 

   `= (7x-8)(7x+8)-10(4x^2+12x+9)+5x(3x-2)^2-4x(x-5)^2`

   `= (7x-8)(7x+8)-10(4x^2+12x+9)+5x(9x^2-12x+4)-4x(x-5)^2`

   `= (7x-8)(7x+8)-10(4x^2+12x+9)+5x(9x^2-12x+4)-4x(x^2-10x+25)`

   `= 49x^2-64-10(4x^2+12x+9)+5x(9x^2-12x+4)-4x(x^2-10x+25)`

   `= 49x^2 – 64 – 40x^2 – 120x – 90 + 45x^3-60x^2+20x-4x^3+40x^2-100x`

   `= 41x^3-11x^2-200x-154`

   `(x^2-3)(x^2+3)-5x^2(x+1)^2-(x^2-3x)(x^2-2x)+4x(x+2)^2`

   `= x^4 – 9 – 5x^2(x+1)-(x^2-3x)(x^2-2x)+4x(x^2+4x+4)`

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

   `= x^4 – 9 – 5x^3 – 5x^2 – x^4 + 5x^3 – 6x^2 + 4x(x^2+4+4)`

   `= x^4 – 9 – 5x^3 – 5x^2 – x^4 + 5x^3 – 6x^2 + 4x^3 + 16x^2 + 16x`

   `= 4x^3 + 5x^2 + 16x -9`

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