2. Решите уравнение: a) -4x + 5,9 = -6,3; б) -2 2/5 * (3/8 * x + 1/4) = 4,5.

Решение: а) \(-4x + 5,9 = -6,3\) \(-4x = -6,3 - 5,9\) \(-4x = -12,2\) \(x = \frac{-12,2}{-4} = 3,05\) б) \(-2 \frac{2}{5} \cdot (\frac{3}{8}x + \frac{1}{4}) = 4,5\) \(-\frac{12}{5} \cdot (\frac{3}{8}x + \frac{1}{4}) = \frac{9}{2}\) \(\frac{3}{8}x + \frac{1}{4} = \frac{9}{2} : (-\frac{12}{5})\) \(\frac{3}{8}x + \frac{1}{4} = \frac{9}{2} \cdot (-\frac{5}{12})\) \(\frac{3}{8}x + \frac{1}{4} = -\frac{3 \cdot 3 \cdot 5}{2 \cdot 3 \cdot 4} = -\frac{15}{8}\) \(\frac{3}{8}x = -\frac{15}{8} - \frac{1}{4} = -\frac{15}{8} - \frac{2}{8} = -\frac{17}{8}\) \(x = -\frac{17}{8} : \frac{3}{8} = -\frac{17}{8} \cdot \frac{8}{3} = -\frac{17}{3} = -5 \frac{2}{3}\)