Compute the following indefinite integrals:

$($a$){\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}(3x^2-2x1)dx$

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

Evaluate the definite integral using substitution:

${\displaystyle \underset{1}{\overset{4}{}}}x\sqrt[\phantom{2}]{x^2-1}dx$