Answer :
To solve the exercise you can use this law of exponents:
[tex]x^m\cdot x^n=x^{m+n}[/tex]So, rewriting the polynomial with the help of the previous law, you have
[tex]\begin{gathered} 2xyx+3yxy^2-3x^2y+5y^3x-6yx^2=2x^{1+1}y+3xy^{2+1}-3x^2y+5y^3x-6yx^2 \\ 2xyx+3yxy^2-3x^2y+5y^3x-6yx^2=2x^2y+3xy^3-3x^2y+5y^3x-6yx^2 \\ \text{ Rearranging the monomials according to the literal part} \\ 2xyx+3yxy^2-3x^2y+5y^3x-6yx^2=2x^2y+3xy^3-3x^2y+5xy^3-6x^2y \end{gathered}[/tex]Finally, operate monomials that have the same literal part
[tex]2xyx+3yxy^2-3x^2y+5y^3x-6yx^2=-7x^2y+8xy^3[/tex]Therefore, the simplified polynomial is
[tex]-7x^2y+8xy^3[/tex]