Let f(x)={3x+21ifx<4x+85ifx>42ifx=4\displaystyle {f{{\left({x}\right)}}}={\left\lbrace\begin{array}{ccc} {3}{x}+{21}&\text{if}&{x}<-{4}\\\sqrt{{{x}+{85}}}&\text{if}&{x}>-{4}\\-{2}&\text{if}&{x}=-{4}\end{array}\right.}

Determine which one of the following rules for continuity is violated at x=4\displaystyle {x}=-{4}.