Well not exactly impossible but ambiguous. However I don't think this one is worthy of another media frenzy. Today's OCR MEI Core 2 paper asks: log_a (a^3)^6 = I think most of you will agree the expected answer is 18. However a significant number of people have given 729 as the answer as they believe the logarithm takes precedence over the final index. Try on your calculator: log (10^3)^6 = or ln (e^3)^6 = Oh dear.