1. 3^(x+3)=81
2. (1/2)^(x-1)=32^x
3. 9*81^(1-2x)=27^(2-x)
4. 10*5^(x-1)+5^(x+1)=7
5. 5^x-(1/5)^(1-x)=4
6. 3^((x^2)-4x)=243
7. 9^x+8*3^x-9=0
8. 1/27*3^(x+2)+2^(2-x)=4