if x is an integer, is 9^x + 9^(-x) = b?
1) 3^x + 3(-x) = sqrt(b+2)
2) x > 0 = b


I understand and can solve (1)
However what is 2)
In the explanation OG says that the given info is NOT SUFFICIENT.

Can somenody please explain what this expression means ??

If i assume that expression means
x>0 and b=0 then
9^x + 9^(-x) = 0 ?
Ans is No as power of 9 or 1/9 will always be +ve and expression will never be 0. Hence should be SUFFICIENT.

somebody Please explain the expression and wha it means.

I just dont understand what it means

thanks!