1. 15u^2+2u+11u+17u^4-10u^4-19u-8u^3

To simplify the given expression, we need to combine like terms. Let's rewrite the expression and group the terms with the same power of \(u\):<br /><br />\[15u^{2} + 2u + 11u + 17u^{4} - 10u^{4} - 19u - 8u^{3}\]<br /><br />Now, let's combine the like terms:<br /><br />\[17u^{4} - 10u^{4} = 7u^{4}\]<br />\[15u^{2}\]<br />\[-8u^{3}\]<br />\[2u + 11u - 19u = -6u\]<br /><br />Putting it all together, we get:<br /><br />\[7u^{4} - 8u^{3} + 15u^{2} - 6u\]<br /><br />So, the simplified expression is:<br /><br />\[7u^{4} - 8u^{3} + 15u^{2} - 6u\]