I can't read the first, third, fourth, fifth and sixth questions. Some brackets would be nice... LaTeX would be even nicer...
Go from here...
Hello, etran3358!
I'll guess what the last one means . . .
3^x-1+3^x+1=30
3^x/3+3.3^x=30
10/3.3^x=30
3^x=9
3^x=3^2
x=2
If my solution is hard to read and understand,
it's because I typed it the way you did ...
no parentheses, no spaces.
This is what I meant . . .
We are given: .3^{x-1} + 3^{x+1} = 30
which equals: .(3^x)/3 + 3(3^x) = 30
add: .(10/3)(3^x) = 30
Multiply by 3/10: .3^x = 9
Hence: .3^x = 3^2
Therefore: .x = 2