Find the slope of the tangent line to the parametric curve {x=t4+2ty=t2+4t\displaystyle {\left\lbrace\begin{array}{c} {x}={t}^{{4}}+{2}{t}\\{y}={t}^{{2}}+{4}{t}\end{array}\right.} at the point t=4\displaystyle {t}={4}