原式=2[

4

3

x-

2

3

x+

1

2

]-

3

4

x

=2[

2

3

x+

1

2

]-

3

4

x

=

4

3

x+1-

3

4

x

=

16

12

x-

9

12

x+1

=

7

12

x+1．