Posted by Erika on Sunday, December 5, 2010 at 11:46pm.
Hints: 1. if u=x^{4}+5 du/dx =d(x^{4}+5)/dx =4x³ or du = 4x³ dx 2. u=√{x² + 3} du/dx = x/√{x² + 3} du = xdx/√{x² + 3} 3. u=? 8x²e^{4}/(x³ +7)