Respuesta :

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(3x² + 2xy + 4y²) + (6x² - 5xy + 3y²) + (9y² - 25y²)

Get rid of the parenthesis :)

3x² + 2xy + 4y² + 6x² - 5xy + 3y² + 9y² - 25y²

Add like terms.

(3x² + 6x²) + (2xy - 5xy) + (4y² + 3y² + 9y² - 25y²)

Simplify.

(9x²) + (-3xy) + (-11y²)

Get rid of the parenthesis.

9x² - 3xy - 11y²

~Hope I helped!~