237. Решите уравнение: a) 2,4 + x = -2,8; б) 18,24 - y = 20; в) 2-(-)=-6.

Решим уравнение:

a) 2,4 + x = -2,8

x = -2,8 - 2,4

x = -5,2

б) 18,24 - y = 20

-y = 20 - 18,24

-y = 1,76

y = -1,76

в) $$2 - (-\frac{4}{27}y) = 6\frac{5}{9}$$

$$2 + \frac{4}{27}y = \frac{6 \cdot 9 + 5}{9}$$

$$\frac{4}{27}y = \frac{54 + 5}{9} - 2$$

$$\frac{4}{27}y = \frac{59}{9} - 2$$

$$\frac{4}{27}y = \frac{59}{9} - \frac{2 \cdot 9}{1 \cdot 9}$$

$$\frac{4}{27}y = \frac{59}{9} - \frac{18}{9}$$

$$\frac{4}{27}y = \frac{41}{9}$$

$$y = \frac{41}{9} : \frac{4}{27}$$

$$y = \frac{41}{9} \cdot \frac{27}{4}$$

$$y = \frac{41 \cdot 3}{4}$$

$$y = \frac{123}{4} = 30\frac{3}{4}$$

Ответ: a) -5,2; б) -1,76; в) $$30\frac{3}{4}$$