(1)4÷5x=20
4÷5x×5x=20×5x
4=100x
100x÷100=4÷100
x=0.04;
(2)2x-6=12
2x-6+6=12+6
2x=18
2x÷2=18÷2
x=9;
(3)x-5÷6=7
x-
=75 6
x-
+5 6
=7+5 6
5 6
x=7
;5 6
(4)1÷2x-8=4
1÷2x-8+8=4+8
1÷2x=12
1÷2x×2x=12×2x
1=24x
24x÷24=1÷24
x=
.1 24