Answer :
From the given expression we get:
[tex](x^5-2x^3+x^2-7)-(2x^5+7x^4-4x^3+2)=x^5-2x^3+x^2-7-2x^5-7x^4+4x^3-2[/tex]Associating similar terms we get:
[tex]\begin{gathered} (x^5-2x^5_{})+(-2x^3+4x^3)+(x^2)+(-7-2) \\ =-x^5+2x^3+x^2-9 \end{gathered}[/tex]