[tex] \frac{ {x}^{2} - 864 }{x} = 12 \sqrt{3 } \\ x ^{2} - 864 = 12 \sqrt{3x} \\ x ^{2} - 864 - 12 \sqrt{3 x} = 0 \\ x ^{2} - 12 \sqrt{3x} - 864 = 0 \\ x1 = \frac{12 \sqrt{3} + \sqrt{3888} }{2} = \frac{12 \sqrt{3} + 36 \sqrt{3} }{2} = 24 \sqrt{3} \\ x2 = \frac{12 \sqrt{3} - \sqrt{3888} }{2} = \frac{12 \sqrt{3} - 36 \sqrt{3} }{2} = -12 \sqrt{3} [/tex]
