Вопрос:

2. Решите уравнение: 1) \(\frac{5}{7}(5,6 - 2,1y) = 2,4(\frac{5}{8} - \frac{2}{3}y)\) 2) \(7,6 : x = 2\frac{1}{9} : 2\frac{4}{9}\)

Ответ:

Решение:

  1. Уравнение 1:
    \(\frac{5}{7}(5,6 - 2,1y) = 2,4(\frac{5}{8} - \frac{2}{3}y)\)
    \(\frac{5}{7}\) * \(5,6\) - \(\frac{5}{7}\) * \(2,1y\) = \(2,4\) * \(\frac{5}{8}\) - \(2,4\) * \(\frac{2}{3}y\)
    \(4 - \frac{10,5}{7}y\) = \(1,5 - \frac{4,8}{3}y\)
    \(4 - 1,5y\) = \(1,5 - 1,6y\)
    \(-1,5y + 1,6y\) = \(1,5 - 4\)
    \(0,1y\) = \(-2,5\)
    \(y\) = \(\frac{-2,5}{0,1}\)
    \(y\) = \(-25\)
  2. Уравнение 2:
    \(7,6 : x = 2\frac{1}{9} : 2\frac{4}{9}\)
    \(7,6 : x = \frac{19}{9} : \frac{22}{9}\)
    \(7,6 : x = \frac{19}{9} \times \frac{9}{22}\)
    \(7,6 : x = \frac{19}{22}\)
    \(x\) = \(7,6 : \frac{19}{22}\)
    \(x\) = \(\frac{76}{10} \times \frac{22}{19}\)
    \(x\) = \(\frac{38}{5} \times \frac{22}{19}\)
    \(x\) = \(\frac{2 \times 19}{5} \times \frac{22}{19}\)
    \(x\) = \(\frac{2 \times 22}{5}\)
    \(x\) = \(\frac{44}{5}\)
    \(x\) = \(8,8\)

Ответ: 1) y = -25; 2) x = 8,8.

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