x=- \frac{1}{6},x= \frac{1}{6}. " alt=" log_{4}(9 x^{2} + \frac{1}{4})=- \frac{1}{2}, 4^{- \frac{1}{2} }=9x^2+ \frac{1}{4}, \frac{1}{ \sqrt{4} } =9x^2 + \frac{1}{4}, \frac{1}{2}=9x^2 + \frac{1}{4}, \\ 2=36x^2 +1,36 x^{2} -1=0,((6x+1)(6x-1)=0=>x=- \frac{1}{6},x= \frac{1}{6}. " align="absmiddle" class="latex-formula">