1. a, A= x²y - 3xy + 3x²y + xy - 1/2x + 5xy - 8/5x - 7 b, B= 5xy² - 3xy + 1/2xy² - xy - 1/3x + 1/2 + 6xy + 2/3x - 1/4

Đáp án:

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`a)` `A = x^2y - 3xy + 3x^2y + xy - 1/2x + 5xy - 8/5x - 7`

`A = ( x^2y + 3x^2y ) + ( - 3xy + 5xy + xy ) - ( 1/2x + 8/5x ) - 7`

`A = ( x^2y + 3x^2y ) + ( - 3xy + 5xy + xy ) - ( 5/10x + 16/10x ) - 7`

`A = 4x^2y + 3xy - 21/10x - 7`

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`b)` `B = 5xy^2 - 3xy + 1/2xy^2 - xy + 1/3x + 1/2 + 6xy + 2/3x - 1/4`

`B = 5xy^2 + 1/2xy^2 + ( -3xy - xy + 6xy ) + ( 1/3x + 2/3x ) - (1/4 - 1/2 )`

`B = 5xy^2 + 1/2xy^2 + 2xy + x + 1/4`

Đáp án:

`a,` ` A= x^²y - 3xy + 3x^²y + xy - 1/2x + 5xy - 8/5x - 7`

`A = (x^2y + 3x^2y) + [(-3xy) + xy + 5xy] + [(-1/2x) - 8/5x] - 7]`

`A = 4x^2y + 3xy - 21/10x - 7`

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`b,` `B= 5xy^² - 3xy + 1/2xy^² - xy - 1/3x + 1/2 + 6xy + 2/3x - 1/4`

`B = (5xy^2 + 1/2xy^2) + [(-3xy) - xy + 6xy] + [(-1/3x) + 2/3x] + (1/2 - 1/4)`

`B = 11/2xy^2 + 2xy + 1/3x + 1/4`

`#dariana`