log 4 x - log 16 x=1\4

log4 x - 1/2log4 x = 1/4log4 x - log4 x^1/2 = 1/4log4 (x/x^1/2)=1/4log4 x^1/2=1/44^1/4=x^1/22^(2*1/4)=x^1/22^1/2=x^1/2x=2