(1)设 0.
•
7 =x,由 0.
•
7 =0.7777…,易得10x=7.777….
可知,10x-x=7.777…-0.777…=7,即 10x-x=7,
解得:x=
7
9 ,
故答案为:
7
9 .
(2)设小数 0.
•
4
•
7 =x,由 0.
•
4
•
7 =0.474747…,易得100x=47.4747…,
可知,100x-x=47.4747…-0.4747…=47,即 100x-x=47,
解得:x=
47
99 ,
即无限循环小数 0.
•
4
•
7 =
47
99 .