X(x-12)+6>81-6x Квадратное уравнения

$x(x-12)+6\ \textgreater \ 81-6x \\ x^2-12x+6-81+6x\ \textgreater \ 0 \\ x^2-6x-75\ \textgreater \ 0 \\ \\ x^2-6x-75=0 \\ D=36+300=336 \\ x_{1}= \frac{6- \sqrt{336} }{2}= \frac{6-4 \sqrt{21} }{2}=3-2 \sqrt{21} \\ x_{2}=3+2 \sqrt{21}$

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______+______3-2√21________-_______3+2√21_______+_________

x∈(-∞;3-2√21)U(3+2√21;+∞)

Ответ: x∈(-∞;3-2√21)U(3+2√21;+∞)