Evaluate the following integrals.

$($a$){\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}cos(x)e^{3x}dx$

$($b$){\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{3x-6}{x(x-3{)}^2}dx$

$($c$){\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{1}{\sqrt[\phantom{2}]{x^2-9}}dx$

$($d$){\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{e^x}{1+e^{2x}}dx$