The first option is correct here: [tex]-13y^4 + 3x^4 - 8x^2y^2 + x^3y + 9x y^3[/tex]
[tex]9xy^3 - 4y^4 - 10x^2y^2 + x^3y + 3x^4 + 2x^2y^2 - 9y^4[/tex]
Combine the like terms together as shown below:
[tex]9xy^3 - 4y^4 - 10x^2y^2 + x^3y + 3x^4 + 2x^2y^2 - 9y^4\\= (-4y^4 - 9y^4) + 9xy^3 + (-10x^2y^2 + 2x^2y^2) +x^3y +3x^4\\= -13y^4 +9xy^3 -8x^2y^2 + x^3y + 3x^4\\= -13y^4 +3x^4 -8x^2y^2 + x^3y + 9xy^3[/tex]
Thus, the first option is correct here: [tex]-13y^4 + 3x^4 - 8x^2y^2 + x^3y + 9x y^3[/tex]
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https://brainly.com/question/10689855
