Chapter 4 - Polynomials - 4.7 Polynomials in Several Variables - 4.7 Exercise Set - Page 284: 29

$3u^2v-11uv^2+11u^2$

By combining like terms, the given expression, $ 6u^2v-9uv^2+3vu^2-2v^2u+11u^2 ,$ simplifies to \begin{array}{l}\require{cancel} (6u^2v+3vu^2)+(-9uv^2-2v^2u)+11u^2 \\\\= 3u^2v-11uv^2+11u^2 .\end{array}