Let $f(x) = \frac{2x+9}{x-7}.$ Find the product of all solutions to the equation $f(f(x)) = x.$
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<|im_start|>user
Let $f(x) = \frac{2x+9}{x-7}.$ Find the product of all solutions to the equation $f(f(x)) = x.$
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-9
Let $f(x) = \frac{2x+9}{x-7}.$ Find the product of all solutions to the equation $f(f(x)) = x.$
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