\[\left( x^{2} - 5 \right)\left( 4x^{2} - x - 5 \right) < (x^{2} - 3)(4x^{2} - x - 5)\]
\[Упростим\ левую\ часть:\]
\[4x^{4} + x^{3} - 5x^{2} - 20x^{2} + 5x + 25 =\]
\[= 4x^{4} - x^{3} - 25x^{2} + 5x + 25\]
\[Упростим\ правую\ часть:\]
\[4x^{4} - x^{3} - 5x^{2} - 12x^{2} + 3x + 15 =\]
\[= 4x^{4} - x^{3} - 17x^{2} + 3x + 15\]
\[4x^{4} - x^{3} - 25x^{2} + 5x + 25 -\]
\[- \left( 4x^{4} - x^{3} - 17x^{2} + 3x + 15 \right) < 0\]
\[4x^{4} - x^{3} - 25x^{2} + 5x + 25 - 4x^{4} + x^{3} +\]
\[+ 17x^{2} - 3x - 15 < 0\]
\[- 8x^{2} + 2x + 10 < 0\]
\[D = 4 + 320 = 324\]
\[x_{1} = \frac{- 2 + 18}{- 16} = - 1;\ \ x_{2} = \frac{- 2 - 18}{- 16} = 1\frac{1}{4}\]
\[(x + 1)(x - 1,25) < 0\]
\[Ответ:x \in ( - \infty; - 1) \cup (1,25; + \infty).\]