Answered
When I enter number 2^3 and I store it in f(x), it's shown in exact form as I wrote it. The same is for (-2)^3, it also stay that way. But when I input -2^3 it changes to -8. This is correct but I need it to stay with base and exponent. Is there a way to do it?
Here is a link: https://ggbm.at/SSDzQEJU
The same question 
One possibility:
Work in Input-Box with text and convert the thext with "ParseToNumber[ <Number>, <String> ]"
work with number instead of function
use for compare of 2 values "==" instead of "=" (for equations)
OMG! This is complicated work-around! But I understood everything you did. Thank you very much! This will help me with what I need!
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