Dunno how to prove it but try the following number all satisfy the criteria, short of time x^2 - 2^x = 0 x= - 0.767 x = 1 x= 2 x= 4 Its been ages I got into these stupid puzzles, and dont waste time thinking. Just answers dears, dont have time. Appreciate it I see all the graphs fail for x=1 bros so forget those stupid graphs