(1)(
4
5 +
1
4 )÷
7
4 +
7
10 ,
=
21
20 ÷
7
4 +
7
10 ,
=
3
5 +
7
10 ,
=
13
10 ;
(2)
2
3 x+
1
2 x=42×30%,
7
6 x=12.6,
7
6 x÷
7
6 =12.6÷
7
6 ,
x=10.8.
(1)(
4
5 +
1
4 )÷
7
4 +
7
10 ,
=
21
20 ÷
7
4 +
7
10 ,
=
3
5 +
7
10 ,
=
13
10 ;
(2)
2
3 x+
1
2 x=42×30%,
7
6 x=12.6,
7
6 x÷
7
6 =12.6÷
7
6 ,
x=10.8.