解方程. 7x+0.7×8=20.6 x-(5/21+3/7)=2/3.

问题描述:

解方程.
7x+0.7×8=20.6                             
x-(

5
21
+
3
7
)=
2
3

(1)7x+0.7×8=20.6
       7x+5.6-5.6=20.6-5.6
            7x÷7=15÷7
                x=2

1
7

(2)x-(
5
21
+
3
7
)=
2
3

            x-
2
3
=
2
3

         x-
2
3
+
2
3
=
2
3
+
2
3

              x=1
1
3