1/2log64+1/2log9-1/2log18+1/2log16=

1/2log64+1/2log9-1/2log18+1/2log16
=1/2log{(64x9)/(18x16)}
=1/2log2
=-1

1/2log64 + 1/2log9 - 1/2log18 + 1/2log16
= 2^-1log2^6 + 1/2log(9/18) + 2^-1log2^4
= (6/-1) 2log2 + 1/2log1/2 + (4/-1) 2log2
= -6 + 1 - 4
= -9