f.4 maths ( log )

=log9/log25 X log5/log27

= log3^2/log5^2 X log5/log3^3
= 2log3/2log5 X log5/3log3
= 1/329.log849^1/2
log327
= [log7/log8]/3log3/log3
= 1/3 X log(base8)7
29題目???

a.log23= log(base5)3/log(base5)2= y/x
b.log(base27)72= log72/log27=log(3^2x2^3)/log3^3
=log3^2/log3^3 + log2^3/log3^3
= 2log3/3log3 + log2/log3
= 2/3 + log(base3)2
= 2/3 + 1/log(base2)3
= 2/3 + x/y