(log以2为底125＋log以4为底25＋log以8为底5）（log以5为底2＋log25为底4＋log以125为底8)
=(lg125/lg2+lg25/lg4+lg5/lg8)(lg2/lg5+lg4/lg25+lg8/lg125)
=(3lg5/lg2+lg5/lg2+1/3lg5/lg2)(lg2/lg5+lg2/lg5+lg2/lg5)
=13/3lg5/lg2*3lg2/lg5
=13/3*3
=13