(1)
1
6 :
4
5 =x:48,
4
5 x=
1
6 ×48,
4
5 x÷
4
5 =
1
6 ×48 ÷
4
5 ,
x=10;
(2)(1+
2
3 )x=6.25,
5
3 x=6.25,
5
3 x÷
5
3 =6.25÷
5
3 ,
x=3.75;
(3)0.26×3-0.9x=6%,
0.78-0.9x=6%,
0.78-0.9x+0.9x=6%+0.9x,
0.78=6%+0.9x,
0.78-6%=6%+0.9x-6%,
0.72=0.9x,
0.72÷0.9=0.9x÷0.9,
x=0.8.