(1)x+
x=3 5
×3 5
2 15
x=8 5
2 25
x×8 5
=5 8
×2 25
5 8
x=
;1 20
(2)40%x-
=1 4
7 12
40%x-
+1 4
=1 4
+7 12
1 4
40%x=
5 6
40%x÷40%=
÷40%5 6
x=
.25 12