123° Вправа 123Алгебра 8 клас Тарасенкова 2025 · § 3 · стор. 39

123. Зведіть до спільного знаменника дроби.

1) ${\displaystyle \frac{1}{b}}$ і ${\displaystyle \frac{1}{5b}}$;

${\displaystyle \frac{1^{\mathrm{\setminus }5}}{b}=}$${\displaystyle \frac{1\cdot 5}{b\cdot 5}=}$${\displaystyle \frac{5}{5b}}$;

${\displaystyle \frac{1}{5b}}$ — без змін;

2) ${\displaystyle \frac{1}{3a}}$ і ${\displaystyle \frac{1}{9a}}$;

${\displaystyle \frac{1^{\mathrm{\setminus }3}}{3a}=}$${\displaystyle \frac{1\cdot 3}{3a\cdot 3}=}$${\displaystyle \frac{3}{9a}}$;

${\displaystyle \frac{1}{9a}}$ — без змін;

3) ${\displaystyle \frac{3}{2ab}}$ і ${\displaystyle \frac{1}{4ac}}$;

${\displaystyle \frac{3^{\mathrm{\setminus }2c}}{2ab}=}$${\displaystyle \frac{3\cdot 2c}{2ab\cdot 2c}=}$${\displaystyle \frac{6c}{4abc}}$;

${\displaystyle \frac{1^{\mathrm{\setminus }b}}{4ac}=}$${\displaystyle \frac{1\cdot b}{4ac\cdot b}=}$${\displaystyle \frac{b}{4abc}}$;

4) ${\displaystyle \frac{5}{a{b}^2}}$ і ${\displaystyle \frac{3}{a^{2}b}}$;

${\displaystyle \frac{5^{\mathrm{\setminus }a}}{a{b}^2}=}$${\displaystyle \frac{5\cdot a}{a{b}^2\cdot a}=}$${\displaystyle \frac{5a}{a^2{b}^2}}$;

${\displaystyle \frac{3^{\mathrm{\setminus }b}}{a^{2}b}=}$${\displaystyle \frac{3\cdot b}{a^{2}b\cdot b}=}$${\displaystyle \frac{3b}{a^2{b}^2}}$.