Calculate the indefinite integrals listed below

a$.{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{3x-9}{\sqrt[\phantom{2}]{x^2-6x+1}}dx$

b$.{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{3-tan}{co{s}^2}d$

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

d$.{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}co{s}^2(3x)dx$