2/5 * x + 1/2 = 4.9
как решить?

Решение:

2/5 * x + 1/2 = 4.9

2/5 * x = 4.9 - 1/2

x = (4.9 - 1/2)/2/5=4,4/0,4=11

Проверка:

2/5 * 11 + 1/2 = 4.9;

4,4+0,5=4,9.

Ответ: 11

2/5*х = 4.9 - 1/2; 1 / 2 = 0,52/5*х = 4.9 - 0.52/5*х = 4.4Х = 4.4 / 2/5; 2 / 5 = 0.4Х = 4.4 / 0.4Х = 44 / 4Х = 11