Find all solutions on the interval $\displaystyle {\left[{0}^{\circ},{360}^{\circ}\right)}$. Round to the nearest hundredth. 

 $\displaystyle {6}{{\cos}^{{2}}{x}}+{18}{\cos{{x}}}+{6}={0}$ 

Separate multiple solutions with a comma. If there are no solutions please enter, "no solution" exactly.