2. Решите уравнения: а) 7-5x = x - 5. б) \(\frac{x-3}{2,4} = \frac{7}{1,2}\) в) \(\frac{x}{2}+\frac{x}{4}+\frac{x}{8}+\frac{x}{16}=5-x \cdot 3\frac{1}{16}\)

Решение:

а) \(7 - 5x = x - 5\) \(7 + 5 = x + 5x\) \(12 = 6x\) \(x = 2\) б) \(\frac{x-3}{2,4} = \frac{7}{1,2}\) \(1,2(x - 3) = 7 \cdot 2,4\) \(1,2x - 3,6 = 16,8\) \(1,2x = 20,4\) \(x = 17\) в) \(\frac{x}{2}+\frac{x}{4}+\frac{x}{8}+\frac{x}{16}=5-x \cdot 3\frac{1}{16}\) \(\frac{8x+4x+2x+x}{16} = 5 - \frac{49}{16}x\) \(\frac{15x}{16} + \frac{49x}{16} = 5\) \(\frac{64x}{16} = 5\) \(4x = 5\) \(x = \frac{5}{4} = 1,25\)

Ответ: а) 2; б) 17; в) 1,25