1); 3^(x+1) - 3^x=18
3^x*(3-1)=18; 3^x=9; 3^x=3^2; x=2
2) log(2) x -log(4) x=6
log(2) x -1/2 *log(2) x=6
1/2 *log(2)x)=6; log(2) x=12; x=2^12
3) log(1/3) (log(3) x)=-1
log(3) x=(1/3)^(-1)
log(3)x=3; x=3^3; x=27
4) 9^x *(9-1)=72
9^x=9; x=1
5)log(3) x -log(9) x=2
log(3) x -1/2log(3) x=2
1/2log(3) x=2; log(3) x=4; x=3^4; x=81
6)log(2) (log(1/2) x)=1
log(1/2) x=2^1
x=(1/2)^2=1/4