4. Решите уравнения a) 2,1 ⋅ (1,2 + x) = 4,2 б) \(\frac{5}{9} + x = 7 \frac{5}{9}\)

4. Решение уравнений:

1. a) \(2.1 \cdot (1.2 + x) = 4.2\)
   \(1.2 + x = \frac{4.2}{2.1}\)
   \(1.2 + x = 2\)
   \(x = 2 - 1.2\)
   \(x = 0.8\)


2. б) \(\frac{5}{9} + x = 7 \frac{5}{9}\)
   \(x = 7 \frac{5}{9} - \frac{5}{9}\)
   \(x = 7 + \frac{5}{9} - \frac{5}{9}\)
   \(x = 7\)

Ответ: а) x = 0,8; б) x = 7.