Question

х - 0.5 = 2 (0.3 х - 0.2)

Answer 1

x-0.5=0.6x-0.4
x-0.6x=-0.4+0.5
0.4x=0.1
x=0.25

Answer 2

x-0.5=0.6x-0.4
домножим на 10
10x-5=6x-4
4x=1
x=1/4=0.25

Проверим:
0.25-0.5=2(0.3*0.25-0.2)
-0.25=0.3*0.5-0.4
-0.25=0.15-0.40
-0.25=-0.25

Вроде так.