Краткое пояснение: Решаем примеры на деление, уравнения и выражения, применяя правила арифметики и алгебры.
1. Выполните деление:
1) 21 : (-7) = -3
2) -52,39 : (-13) = 4,03
3) \(\frac{15}{34} : (-\frac{45}{51}) = \frac{15}{34} \cdot (-\frac{51}{45}) = -\frac{15 \cdot 51}{34 \cdot 45} = -\frac{1 \cdot 3}{2 \cdot 3} = \) -\(\frac{1}{2}\)
4) -1\(\frac{7}{18}\) : 5\(\frac{2}{5}\) = -\(\frac{25}{18}\) : \(\frac{27}{5}\) = -\(\frac{25}{18} \cdot \frac{5}{27}\) = -\(\frac{125}{486}\)
2. Решите уравнение:
1) -5x = 45
x = 45 : (-5)
x = -9
2) 0,6x = -1,8
x = -1,8 : 0,6
x = -3
3) -1,6x = -9,6
x = -9,6 : (-1,6)
x = 6
4) \(\frac{1}{3}\)x = -\(\frac{2}{9}\)
x = -\(\frac{2}{9}\) : \(\frac{1}{3}\)
x = -\(\frac{2}{9} \cdot \frac{3}{1}\)
x = -\(\frac{2}{3}\)
x = -\(\frac{2}{3}\)
5) -\(\frac{2}{7}\)x = -\(\frac{1}{3}\)
x = -\(\frac{1}{3}\) : (- \(\frac{2}{7}\))
x = \(\frac{1}{3} \cdot \frac{7}{2}\)
x = \(\frac{7}{6}\) = 1\(\frac{1}{6}\)
6) -2\(\frac{1}{3}\)x = \(\frac{7}{15}\)
-\(\frac{7}{3}\)x = \(\frac{7}{15}\)
x = \(\frac{7}{15}\) : (- \(\frac{7}{3}\))
x = \(\frac{7}{15} \cdot (-\frac{3}{7})\)
x = -\(\frac{1}{5}\)
x = -\(\frac{1}{5}\)
3. Выполните действия:
1) 3,2 ⋅ (-6) - 7,8 : (8,8 – 10,1) = -19,2 - 7,8 : (-1,3) = -19,2 - (-6) = -19,2 + 6 = -13,2
2) (-1,2 + 4,32 : (-1,8)) : (-0,01) : (-0,3) = (-1,2 + (-2,4)) : (-0,01) : (-0,3) = -3,6 : (-0,01) : (-0,3) = 360 : (-0,3) = -1200
4. Найдите значение выражения:
1) (\(\frac{5}{18} + \frac{11}{12}\)) : \(\frac{69}{72}\) = (\(\frac{10}{36} + \frac{33}{36}\)) : \(\frac{69}{72}\) = \(\frac{43}{36}\) : \(\frac{69}{72}\) = \(\frac{43}{36} \cdot \frac{72}{69}\) = \(\frac{43 \cdot 2}{1 \cdot 69}\) = \(\frac{86}{69}\) = 1\(\frac{17}{69}\)
2) (\(\frac{11}{18} + \frac{29}{45}\)) : (\(\frac{35}{54} - \frac{19}{27}\)) = (\(\frac{55}{90} + \frac{58}{90}\)) : (\(\frac{35}{54} - \frac{38}{54}\)) = \(\frac{113}{90}\) : (-\(\frac{3}{54}\)) = \(\frac{113}{90} \cdot (-\frac{54}{3})\) = -\(\frac{113 \cdot 6}{10 \cdot 3}\) = -\(\frac{113}{5} \) = -22\(\frac{3}{5}\)
3) (\(\frac{5}{12} - \frac{13}{15}\)) : (-\(\frac{9}{14} + \frac{24}{35}\)) = (\(\frac{25}{60} - \frac{52}{60}\)) : (-\(\frac{45}{70} + \frac{48}{70}\)) = (-\(\frac{27}{60}\)) : (\(\frac{3}{70}\)) = -\(\frac{27}{60} \cdot \frac{70}{3}\) = -\(\frac{9 \cdot 7}{6}\) = -\(\frac{3 \cdot 7}{2}\) = -\(\frac{21}{2}\) = -10\(\frac{1}{2}\)
Ответ: Смотри решение выше