\[\frac{12b^{2} - x}{4b} - 3x^{\backslash 4b} =\]
\[= \frac{12b^{2} - x - 12xb}{4b} =\]
\[= \frac{12b(b - x) - x}{4b} =\]
\[= 3(b - x) - \frac{x}{4b};\]
\[b = - 0,35 = - \frac{35}{100} = - \frac{7}{20};\ \ x = 28:\]
\[3 \cdot \left( - \frac{7}{20} - 28^{\backslash 20} \right) - \frac{28}{4 \cdot ( - 0,35)} =\]
\[= 3 \cdot \left( - \frac{567}{20} \right) - \frac{28}{- 1,4} =\]
\[= - 85,05 - 20 = - 105,05.\]