Verified answer

Ответ:

1)x + x+3.7 = 15.9

2x +3.7 =15.9

2x = 15.9 -3.7

2x = 12.2

x = 6.1

2) x + x -5.4 = 19.8

2x -5.4 = 19.8

2x = 25.2

x = 12.6

Пошаговое объяснение: