You would use some properties of the logarithm. First, [tex]log_927=log_{3^2}27=\frac{1}{2}log_327[/tex]. So, now you have [tex]log_327[/tex] to calculate. It's [tex]log_33^3=3[/tex], so the final result is [tex]\frac{1}{2}*3=\frac{3}{2}[/tex]
Hope it helps.