(1)0.8x-0.4=1.2,
0.8x-0.4+0.4=1.2+0.4,
0.8x=1.6,
0.8x÷0.8=1.6÷0.8,
x=2;
(2)x-25%x=36,
0.75x=36,
0.75x÷0.75=36÷0.75,
x=48;
(3)
x+x=4,7 9
x=4,16 9
x÷16 9
=4÷16 9
,16 9
x=
.9 4