Respuesta :

[tex](4x^2-9x+4)+(7x^3-9x)[/tex]

we remove the parenthesis and add the number that have the same exponent

[tex]\begin{gathered} 4x^2-9x+4+7x^3-9x \\ 7x^3+4x^2+(-9x-9x)+4 \\ 7x^3+4x^2-18x+4 \end{gathered}[/tex]

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