\[{\text{Разделите уравнение на }}{\left( {x - 3} \right)^2}.\]

\[\begin{array}{l}{\text{Делим уравнение на }}{\left( {x - 3} \right)^2}.\\3{\left( {\frac{{{x^2}}}{{x - 3}}} \right)^2} + 14\frac{{{x^2}}}{{x - 3}} - 5 = 0\\{\text{Замена }}\frac{{{x^2}}}{{x - 3}} = t\\3{t^2} + 14t - 5 = 0 \Leftrightarrow \left[ \begin{array}{l}t = - 5\\t = \frac{1}{3}\end{array} \right.\\\frac{{{x^2}}}{{x - 3}} = - 5 \Leftrightarrow x = \frac{{ - 5 \pm \sqrt {85} }}{2}\\\frac{{{x^2}}}{{x - 3}} = \frac{1}{3}{\text{ решений нет}}\end{array}\]

\[\frac{{ - 5 \pm \sqrt {85} }}{2}\]