A basic log transition is x=log_b(a)x=logb(a) to a=b^xa=bx.
If you plug in the variables of a=1/9a=19, b=3b=3, and x=-2x=โ2, you can go from a=b^xa=bx (or 3^-2=1/93โ2=19 if you input the variables) to x=log_b(a)x=logb(a), which is equivalent to -2=log_3(1/9)โ2=log3(19) if you plug in the variables.