Đáp án + giải thích các bước giải:

`(-2x^2)(x^2-2x+3).1/2`

`= 1/2 . (-2x^4 + 4x^3 -6x^2)`

`= -x^4 + 2x^3 - 3x^2`

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`(2/3 xy^2)(x^2y - xy + x/2 + 1/4)`

`2/3x^3y^3 - 2/3x^2y^3 - 1/3 x^2y^2 + 1/6xy^2`

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`(-2x+1)(2x^2 - 1/3x + 2)`

`= (-2x)(2x^2 - 1/3x + 2) + 2x^2 - 1/3x + 2`

`= -4x^2 + 2/3x^2 - 4x + 2x^2 - 1/3x + 2`

`= (-4x^2 + 2/3x^2 + 2x^2) + (-4x - 1/3x) + 2`

`= -4/3x^2 - 13/3x + 2`

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`(x+y^2)(x^2+1/2y + 3/2xy)`

`= x(x^2+1/2y + 3/2xy) + y^2 (x^2+1/2y + 3/2xy)`

`= x^3 + 1/2 xy + 3/2 x^2y + x^2 y^2 + 1/2 y^3 + 3/2 xy^3`