Evaluate the following integrals

A$.){\displaystyle \underset{1}{\overset{3}{}}}1+x^{2}dx$

B$.){\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}{x}^2(x+2)dx$

C$.){\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\sqrt[\phantom{2}]{x}-\frac{8}{x}dx$