1107. Раскрытие скобок и приведение подобных слагаемых
- \(\frac{2}{3}\left(-\frac{3}{8}x + 6\right) - \frac{3}{7}\left(28 - \frac{7}{12}x\right) = \frac{2}{3} \cdot \left(-\frac{3}{8}x\right) + \frac{2}{3} \cdot 6 - \frac{3}{7} \cdot 28 + \frac{3}{7} \cdot \frac{7}{12}x = \left(-\frac{2 \cdot 3}{3 \cdot 8}\right)x + 4 - 12 + \frac{3 \cdot 7}{7 \cdot 12}x = -\frac{1}{4}x - 8 + \frac{1}{4}x = (- \frac{1}{4} + \frac{1}{4})x - 8 = 0x - 8 = -8\).
- \(-\frac{2}{9}\left(2,7x - 1\frac{1}{2}y\right) - 1\frac{1}{6}\left(2,4x - 1\frac{5}{7}y\right) = \left(-\frac{2}{9} \cdot 2,7x + \frac{2}{9} \cdot 1,5y\right) - \left(1\frac{1}{6} \cdot 2,4x - 1\frac{1}{6} \cdot 1\frac{5}{7}y\right) = \left(-\frac{2}{9} \cdot \frac{27}{10}x + \frac{2}{9} \cdot \frac{3}{2}y\right) - \left(\frac{7}{6} \cdot \frac{24}{10}x - \frac{7}{6} \cdot \frac{12}{7}y\right) = \left(-\frac{2 \cdot 27}{9 \cdot 10}x + \frac{2 \cdot 3}{9 \cdot 2}y\right) - \left(\frac{7 \cdot 24}{6 \cdot 10}x - \frac{7 \cdot 12}{6 \cdot 7}y\right) = \left(-\frac{6}{10}x + \frac{1}{3}y\right) - \left(\frac{28}{10}x - 2y\right) = -0,6x + \frac{1}{3}y - 2,8x + 2y = (-0,6 - 2,8)x + (\frac{1}{3} + 2)y = -3,4x + (\frac{1}{3} + \frac{6}{3})y = -3,4x + \frac{7}{3}y\).
Ответ: 1) -8; 2) -3,4x + \(\frac{7}{3}\)y.