Đáp án + Giải thích các bước giải:

`a) (12 x^4.y^2 – 20x^3.y^3 + 32x^2y^4) : (-8x^2y^2)`

`= -3/2x^2 + 5/2xy - 4y^2`

`b) [15x^3.(3x –y)^3 + 10x^2(y –3x)^2 – 25x(3x –y)] : [-5x.(3x –y)]` 

`= -3x^2(3x-y)^2 + 2x(3x-y) + 5`

`= -3x^2(9x^2-6xy+y^2) + 6x^2 - 2xy + 5`

`= -27x^4 + 18x^3 - 3x^2y^2 + 6x^2  - 2xy + 5`

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