Краткий ответ
108.
- а) \(\displaystyle \frac{10b}{9a}\)
- б) \(\displaystyle \frac{7a}{16y}\)
- в) \(\displaystyle \frac b2\)
- г) \(\displaystyle \frac{3}{4c}\)
109.
- а) \(\displaystyle \frac{5}{2xy}\)
- б) \(\displaystyle \frac{a}{b^2}\)
- в) \(\displaystyle \frac{7a^3b}{3}\)
- г) \(\displaystyle \frac{2a}{3b^2}\)
110.
- а) \(\displaystyle \frac{x^2}{5a}\)
- б) \(\displaystyle \frac{2}{15m}\)
- в) \(\displaystyle \frac{22b}{a}\)
- г) \(\displaystyle \frac{6n^2}{m}\)
111.
- а) \(\displaystyle \frac{35}{2x}\)
- б) \(\displaystyle \frac{25}{8}\)
- в) \(\displaystyle \frac{8a^2}{m}\)
- г) \(\displaystyle \frac{4b}{a}\)
№112 на фото обрезан, поэтому его условие полностью не видно.
Решение
Используем правило:
\[ \frac ab\cdot\frac cd=\frac{ac}{bd}, \]
после чего сокращаем общие множители.
№108
\[ \text{а)}\quad \frac{5}{3a}\cdot\frac{2b}{3} =\frac{10b}{9a}. \]
\[ \text{б)}\quad \frac{5a}{8y}\cdot\frac{7}{10} =\frac{35a}{80y} =\frac{7a}{16y}. \]
\[ \text{в)}\quad \frac{b^2}{10}\cdot\frac{5}{b} =\frac{5b^2}{10b} =\frac b2. \]
\[ \text{г)}\quad \frac{18}{c^4}\cdot\frac{c^3}{24} =\frac{18c^3}{24c^4} =\frac{3}{4c}. \]
№109
\[ \text{а)}\quad \frac{3x}{4y}\cdot\frac{10}{3x^2} =\frac{30x}{12x^2y} =\frac{5}{2xy}. \]
\[ \text{б)}\quad \frac{2{,}5}{2a^2}\cdot\frac{4a^3}{5b^2} =\frac{10a^3}{10a^2b^2} =\frac{a}{b^2}. \]
\[ \text{в)}\quad \frac{7a^3}{24b}\cdot 8b^2 =\frac{56a^3b^2}{24b} =\frac{7a^3b}{3}. \]
\[ \text{г)}\quad 14ab\cdot\frac1{21b^3} =\frac{14ab}{21b^3} =\frac{2a}{3b^2}. \]
№110
\[ \text{а)}\quad \frac{12}{5x}\cdot\frac{x^3}{12a} =\frac{x^3}{5ax} =\frac{x^2}{5a}. \]
\[ \text{б)}\quad \frac{8c^2}{15m}\cdot\frac1{4c^2} =\frac{8}{60m} =\frac{2}{15m}. \]
\[ \text{в)}\quad \frac{11a^4}{6}\cdot\frac{12b}{a^5} =\frac{132a^4b}{6a^5} =\frac{22b}{a}. \]
\[ \text{г)}\quad \frac{4n^2}{3m^2}\cdot\frac{9m}{2} =\frac{36n^2m}{6m^2} =\frac{6n^2}{m}. \]
№111
\[ \text{а)}\quad 15x^2\cdot\frac{7}{6x^3} =\frac{105x^2}{6x^3} =\frac{35}{2x}. \]
\[ \text{б)}\quad \frac{25}{16y^2}\cdot2y^2 =\frac{50y^2}{16y^2} =\frac{25}{8}. \]
\[ \text{в)}\quad 6am^2\cdot\frac{4a}{3m^3} =\frac{24a^2m^2}{3m^3} =\frac{8a^2}{m}. \]
\[ \text{г)}\quad \frac{2b}{5a^3}\cdot10a^2 =\frac{20a^2b}{5a^3} =\frac{4b}{a}. \]
Проверка основана на сокращении одинаковых множителей: например, \(c^3/c^4=1/c\), \(b^2/b=b\), \(a^4/a^5=1/a\).
