\[\boxed{\text{27.}\text{\ }еуроки - ответы\ на\ пятёрку}\]
\[\textbf{а)}\ 12 = 24\ :4 + 6\]
\[\textbf{б)}\ 0 = 18 - 6 \cdot 3\]
\[\boxed{\text{27\ (27).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[при\ a - b = 4:\]
\[\frac{12}{b - a} + \frac{16}{(b - a)^{2}} =\]
\[= \frac{12}{- (a - b)} + \frac{16}{\left( - (a - b) \right)^{2}} =\]
\[= \frac{16}{(a - b)^{2}} - \frac{12^{\backslash a - b}}{(a - b)} =\]
\[= \frac{16 - 12 \cdot (a - b)}{(a - b)^{2}} =\]
\[= \frac{16 - 12 \cdot 4}{4^{2}} = \frac{16 - 48}{16} =\]
\[= - \frac{32}{16} = - 2.\]
\[Ответ:1)\ - 2.\]