Упростите выражение и найдите его значение:
1) $\frac{1}{2}a + \frac{1}{3}a - \frac{1}{4}a$, если a = $1\frac{5}{7}$;
2) $\frac{4}{7}b + \frac{5}{21}b - \frac{2}{3}b$, если b = $2\frac{1}{3}$;
3) $1\frac{5}{12}m + 2\frac{7}{18}m - 1\frac{2}{9}m$, если m = $1\frac{17}{31}$.
$\frac{1}{2}a + \frac{1}{3}a - \frac{1}{4}a = \frac{6}{12}a + \frac{4}{12}a - \frac{3}{12}a = \frac{7}{12}a = \frac{7}{12} * 1\frac{5}{7} = \frac{7}{12} * \frac{7}{12} = 1$
$\frac{4}{7}b + \frac{5}{21}b - \frac{2}{3}b = \frac{12}{21}b + \frac{5}{21}b - \frac{14}{21}b = \frac{3}{21}b = \frac{1}{7}b = \frac{1}{7} * 2\frac{1}{3} = \frac{1}{7} * \frac{7}{3} = \frac{1}{3}$
$1\frac{5}{12}m + 2\frac{7}{18}m - 1\frac{2}{9}m = 1\frac{15}{36}m + 2\frac{14}{36}m - 1\frac{8}{36}m = 2\frac{7}{12}m = \frac{31}{12} * 1\frac{17}{31} = \frac{31}{12} * \frac{48}{31} = \frac{1}{1} * \frac{4}{1} = 4$
Пожауйста, оцените решение
