(1)x-
7
8 =
7
8 ,
x-
7
8 +
7
8 =
7
8 +
7
8 ,
x=
7
4 ;
(2)
2
5 +x=
3
2 ,
2
5 +x-
2
5 =
3
2 -
2
5 ,
x=
11
10 ;
(3)3x=4,
3x÷3=4÷3,
x=
4
3 ;
(4)x÷0.4=0.16,
x÷0.4×0.4=0.16×0.4,
x=0.064.
(1)x-
7
8 =
7
8 ,
x-
7
8 +
7
8 =
7
8 +
7
8 ,
x=
7
4 ;
(2)
2
5 +x=
3
2 ,
2
5 +x-
2
5 =
3
2 -
2
5 ,
x=
11
10 ;
(3)3x=4,
3x÷3=4÷3,
x=
4
3 ;
(4)x÷0.4=0.16,
x÷0.4×0.4=0.16×0.4,
x=0.064.