\[64x + x^{- 1} = - 16\ \ \ | \cdot x\]
\[64x^{2} + x^{0} = - 16x\]
\[64x^{2} + 16x + 1 = 0\]
\[(8x + 1)^{2} = 0\]
\[8x + 1 = 0\]
\[8x = - 1\]
\[x = - \frac{1}{8}.\]
\[Ответ:x = - \frac{1}{8}.\]