X=?

[Relativity]

For easy lets call the number we are after for X. X^2 have the same value as X+1. If you use X as a base for a numeral system, you will have to write 10,01 to get the value 2 in our 10 based system. what number is it? write it whit 3 decimals

[sazdreamer]

but this science not maths

[dan19_83]

are there two answers?

[(1 + (square root of 5))/2] and [(1 - (square root of 5))/2]