\[(2 - x)(2 + x)\left( 4 + x^{2} \right) + \left( 6 - x^{2} \right)^{2} =\]
\[= \left( 4 - x^{2} \right)\left( 4 + x^{2} \right) + \left( 6 - x^{2} \right)^{2} =\]
\[= 16 - x^{4} + 36 - 12x^{2} + x^{4} =\]
\[= - 12x^{2} + 48\]
\[x = - \frac{1}{2}:\]
\[- 12 \cdot \left( - \frac{1}{2} \right)^{2} + 48 = - 12 \cdot \frac{1}{4} + 48 =\]
\[= - 3 + 48 = 45.\]