Respuesta :

1.
x = 0.212121...
100x = 21.212121...
99x = 100x - x = 21.2121... - 0.2121.. = 21
x = 21/99

2.
3.7 = 3 + 0.7
0.7 as a fraction is 7/10
so 3.7 is 3 7/10