6) 5 12 -в при в=1 b = 5 5 6 84 b = 12' b = 5' b = 25' b = 0.

Найдём значение выражения: а) $$\frac{5}{12}b$$ при $$b = \frac{1}{5}$$: $$\frac{5}{12} \cdot \frac{1}{5} = \frac{5 \cdot 1}{12 \cdot 5} = \frac{1}{12}$$ б) $$\frac{5}{12}b$$ при $$b = \frac{5}{12}$$: $$\frac{5}{12} \cdot \frac{5}{12} = \frac{5 \cdot 5}{12 \cdot 12} = \frac{25}{144}$$ в) $$\frac{5}{12}b$$ при $$b = \frac{6}{5}$$: $$\frac{5}{12} \cdot \frac{6}{5} = \frac{5 \cdot 6}{12 \cdot 5} = \frac{6}{12} = \frac{1}{2}$$ г) $$\frac{5}{12}b$$ при $$b = \frac{84}{25}$$: $$\frac{5}{12} \cdot \frac{84}{25} = \frac{5 \cdot 84}{12 \cdot 25} = \frac{5 \cdot 12 \cdot 7}{12 \cdot 5 \cdot 5} = \frac{7}{5} = 1\frac{2}{5}$$ д) $$\frac{5}{12}b$$ при $$b = 0$$: $$\frac{5}{12} \cdot 0 = 0$$ Ответ: а) $$\frac{1}{12}$$, б) $$\frac{25}{144}$$, в) $$\frac{1}{2}$$, г) $$1\frac{2}{5}$$, д) $$0$$