Ineed to simplify this (3x^2+2xy+4y^2) + (6x^2-5xy+3y^2) + (9y^2-25y^2)

(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!~

The correct answer is -20y