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Решите задачу:

$\dfrac{1}{ \frac{1}{3} - \frac{1}{4}} \ = \ \dfrac{1}{ \frac{4}{12} - \frac{3}{12}} \ = \ \dfrac{1}{ \frac{1}{12} } \ = \ 1: \dfrac{1}{12} \ = \ \dfrac{1}{1} : \dfrac{1}{12} \ = \ \dfrac{1}{1} \cdot \dfrac{12}{1} \ = \ \dfrac{12\cdot1}{1\cdot1} \ = \$

$= \dfrac{12\cdot1}{1\cdot1} \ = \dfrac{12}{1} = 12:1 = \boldsymbol{12;} \\ \\ \\ \\ \\ \boxed{\boldsymbol{OTBET:12}}$