Ответ:

  1. \(1.23x - 1.229x = 1.8\).
    \((1.23 - 1.229)x = 1.8\).
    \(0.001x = 1.8\).
    \(x = 1.8 : 0.001 = 1800\).
  2. \((x + 2.4) \cdot 0.18 = 61.2\).
    \(x + 2.4 = 61.2 : 0.18 = 340\).
    \(x = 340 - 2.4 = 337.6\).

Ответ: 1) x = 1800; 2) x = 337,6.