log8 9=lg9/lg8=2lg3/3lg2=a
lg3=3/2*lg2*a
log3 5=lg5/lg3=(1-lg2)/lg3=b
1-lg2=lg3*b
1-lg2=3/2*lg2*a*b
1=(1+3ab/2)*lg2
lg2=2/(2+3ab)