Solution 3.3:4c

From Förberedande kurs i matematik 1

All three arguments of the logarithm can be written as powers of 3,

273191=3331=3331=31=3=132=3−2

and it is therefore appropriate to use base 3 when simplifying using the logarithms, even if we have the base 10-logarithm, lg,

lg2731+2lg3+lg91=lg3+21lg3+lg3−2=lg3+21lg3+(−2)lg3=1+21−2lg3=−21lg3.

This expression cannot be simplified any further.