\[ -14.4x^2 = -3.6 \]
\[ x^2 = \frac{-3.6}{-14.4} \]
\[ x^2 = \frac{3.6}{14.4} = \frac{36}{144} = \frac{1}{4} \]
\[ x = \pm \sqrt{\frac{1}{4}} \]
Ответ: -0.5