1991 AIME, Problem 7

Find $A^2$, where is $A$ the sum of the absolute values of all roots of the following equation:

$x = \sqrt{19} + \dfrac{91}{{\sqrt{19}+\dfrac{91}{{\sqrt{19}+\dfrac{91}{{\sqrt{19}+\dfrac{91}{{\sqrt{19}+\dfrac{91}{x}}}}}}}}}$

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