Let
\[f(x) = \frac{cx}{2x + 3}.\]Find the constant $c$ so that $f^{-1}(x) = f(x).$
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Let
\[f(x) = \frac{cx}{2x + 3}.\]Find the constant $c$ so that $f^{-1}(x) = f(x).$
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-3
Let
\[f(x) = \frac{cx}{2x + 3}.\]Find the constant $c$ so that $f^{-1}(x) = f(x).$
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