\[\boxed{\text{1252.\ }\text{еуроки}\text{-}\text{ответы}\text{\ }\text{на}\text{\ }\text{пятёрку}}\]
\[\textbf{а)}\frac{am^{- 2}}{a^{- 1}b} = \frac{a \cdot a}{bm^{2}} = \frac{a^{2}}{bm^{2}}\]
\[\textbf{б)}\ \frac{(a + b)b}{b^{- 1}(a - b)} = \frac{(a + b)b \cdot b}{(a - b)} =\]
\[= \frac{(a + b)b^{2}}{(a - b)}\]
\[\textbf{в)}\ \frac{2a^{- 1}b²}{(a + b)^{- 2}} = \frac{2b²(a + b)²}{a}\]