решите уравнение
3,7+(2/5 - х) = 3,2

2/5=0.4 3.7+(0.4-х) =3.2 0.4-х=3.2-3.7 0.4-х=-0.5 0.4+0.5=х х=0.9 Проверка 3.7+(0.4-0.9)=3.2 3.7-0.5=3.2 3.2=3.2