.
Strictly saying, this equation 
= 0.3 has infinitely many different solutions
on the number line; respectively, expression 
may have infinitely many different values,
and I do not think that they expect to get this infinite set of values as an answer.
I explain it to the Math composer in order for he (or she) get understanding, that such problem
should have reasonable restrictions on the diapason of values of 
- then the problem
will be more reasonable (will be posed more professionally).
