Question Number 24966 by math solver last updated on 30/Nov/17
$$\mathrm{find}\:\mathrm{the}\:\mathrm{focus}\:\mathrm{of}\:\mathrm{the}\:\mathrm{hyperbola}\: \\ $$$${x}^{\mathrm{2}} −\mathrm{16}{xy}−\mathrm{11}{y}^{\mathrm{2}} −\mathrm{12}{x}+\mathrm{6}{y}+\mathrm{21}=\mathrm{0}\:? \\ $$
Commented by math solver last updated on 30/Nov/17
$$\sqrt{?\sqrt{?\sqrt{?}}} \\ $$