解方程. 9x-4x=6.5; 1/4+x=1/2; y-2/5=3/4; m+3/5=7/10.

问题描述:

解方程.   
9x-4x=6.5;         

1
4
+x=
1
2
;        y-
2
5
=
3
4
;          m+
3
5
=
7
10

(1)9x-4x=6.5
           5x=6.5
        5x÷5=6.5÷5
            x=1.3;
(2)

1
4
+x=
1
2

 
1
4
+x-
1
4
=
1
2
-
1
4

       x=
1
4

(3)y-
2
5
=
3
4

  y-
2
5
+
2
5
=
3
4
+
2
5

       y=
23
20

(4)m+
3
5
=
7
10

  m+
3
5
-
3
5
=
7
10
-
3
5

       m=
1
10