选择适当的方法计算下列各题.2212×6%+2.75÷123+1.2;119÷[3225-(32.4-

选择适当的方法计算下列各题.2212×6%+2.75÷123+1.2;119÷[3225-(32.4-13×0.25)]×12;4x-3(2-x)=5x;5x+34=2x+534.

(1)22
1
2
×6%+2.75÷1
2
3
+1.2
=
27
20
+
33
20
+1.2
=3+1.2
=4.2;

(2)1
1
9
÷[32
2
5
-(32.4-
1
3
×0.25)]×12
=1
1
9
÷[32
2
5
-(32.4-
1
12
)]×12
=1
1
9
÷[32
2
5
-32.4+
1
12
)]×12
=1
1
9
÷(0+
1
12
)×12
=
10
9
×12×12
=
40
3
×12
=160;

(3)4x-3(2-x)=5x
        4x-6+3x=5x
           7x-6=5x
        7x-6-5x=5x-5x
         2x-6+6=0+6
             2x=6
          2x÷2=6÷2
              x=3;

(4)5x+
3
4
=2x+5
3
4

  5x+
3
4
-2x=2x+5
3
4
-2x
     3x+
3
4
=5
3
4

   3x+
3
4
-
3
4
=5
3
4
-
3
4

     3x÷3=5÷3
         x=
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