27x-12x=48
(27-12)x=48
15x=48
x=48/15=16/5
2.5×5-4x=0.25
4x=0.25-12.5
4x=-12.25
x=-12.25÷4
x=-3.0625
6x-18.6=28.5
6x=28.5+18.6=47.1
x=47.1÷6=7.85
65×0.3-7x=3.4
7x=19.5-3.4=16.1
x=16.1÷7=2.3