1) log10 (3x+6)=2log10 4 + log10 3
2) log7 (2x^2 - 5x + 31)=2
3) log10 x^2 +9log10 x^2 =40
4) 4^logx(1/3)^-1 = 0.5
5) log1/3 (x+1)+2 log1/3 (x-1) = log1/3 (1-x^2) +2
6) log2 log3x =1