Ответ:

  1. \(18\frac{2}{17}-(3\frac{5}{17}+x)=5\frac{5}{17}\).

    \(3\frac{5}{17}+x=18\frac{2}{17}-5\frac{5}{17}=12\frac{14}{17}\).

    \(x=12\frac{14}{17}-3\frac{5}{17}=9\frac{9}{17}\).

  2. \(2.7x-1.84x+5.87=8.88\).

    \(0.86x=8.88-5.87=3.01\).

    \(x=3.01:0.86=3.5\).

Ответ: 1) \(x=9\frac{9}{17}\); 2) \(x=3,5\).