39. Решите уравнение: 1) 0,8 – (1,5x – 2) = -0,8 + 4,5x; 2) 0,6x – 5 (0,3x + 0,2) = 0,5 (x – 1) – 0,8; 3) \(\frac{1}{7}(\frac{7}{8}y+7)-\frac{3}{4}(\frac{2}{9}y+1\frac{7}{9})=\frac{1}{12}\); 4) \(\frac{5}{27}(5,4-8,1y)=0,03+\frac{4}{17}(6,8-3,4y)\).

1) Решение уравнения:

\(0,8 - (1,5x - 2) = -0,8 + 4,5x\)

\(0,8 - 1,5x + 2 = -0,8 + 4,5x\)

\(2,8 - 1,5x = -0,8 + 4,5x\)

\(2,8 + 0,8 = 4,5x + 1,5x\)

\(3,6 = 6x\)

\(x = \frac{3,6}{6}\)

\(x = 0,6\)

Ответ: \(x = 0,6\).

2) Решение уравнения:

\(0,6x - 5(0,3x + 0,2) = 0,5(x - 1) - 0,8\)

\(0,6x - 1,5x - 1 = 0,5x - 0,5 - 0,8\)

\(-0,9x - 1 = 0,5x - 1,3\)

\(-1 + 1,3 = 0,5x + 0,9x\)

\(0,3 = 1,4x\)

\(x = \frac{0,3}{1,4}\)

\(x = \frac{3}{14}\)

Ответ: \(x = \frac{3}{14}\).

3) Решение уравнения:

\(\frac{1}{7}(\frac{7}{8}y+7)-\frac{3}{4}(\frac{2}{9}y+1\frac{7}{9})=\frac{1}{12}\)

\(\frac{1}{7}(\frac{7}{8}y+7)-\frac{3}{4}(\frac{2}{9}y+\frac{16}{9})=\frac{1}{12}\)

\(\frac{1}{8}y+1-\frac{6}{36}y-\frac{48}{36}=\frac{1}{12}\)

\(\frac{1}{8}y+1-\frac{1}{6}y-1\frac{1}{3}=\frac{1}{12}\)

\(\frac{3-4}{24}y = \frac{1}{12} + 1\frac{1}{3}\)

\(-\frac{1}{24}y = \frac{1}{12} + \frac{4}{3}\)

\(-\frac{1}{24}y = \frac{1+16}{12}\)

\(-\frac{1}{24}y = \frac{17}{12}\)

\(y = \frac{17}{12} \times (-24)\)

\(y = 17 \times (-2)\)

\(y = -34\)

Ответ: \(y = -34\).

4) Решение уравнения:

\(\frac{5}{27}(5,4-8,1y)=0,03+\frac{4}{17}(6,8-3,4y)\)

\(\frac{5 \times 5,4}{27} - \frac{5 \times 8,1}{27}y = 0,03 + \frac{4 \times 6,8}{17} - \frac{4 \times 3,4}{17}y\)

\(\frac{27}{27} - \frac{40,5}{27}y = 0,03 + \frac{27,2}{17} - \frac{13,6}{17}y\)

\(1 - 1,5y = 0,03 + 1,6 - 0,8y\)

\(1 - 1,5y = 1,63 - 0,8y\)

\(1 - 1,63 = 1,5y - 0,8y\)

\(-0,63 = 0,7y\)

\(y = \frac{-0,63}{0,7}\)

\(y = -0,9\)

Ответ: \(y = -0,9\).