Evaluate the integral by making the given substitution. $($Use $C$ for the constant of integration.$)$

${\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}co{s}^7()sin()d,u=cos()$

Evaluate the indefinite integral. $($Remember the constant of integration.$)$

${\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}(x+4)\sqrt[\phantom{2}]{8x+x^2}dx$