log2 3=a
∴log3 2=1/a
log(14)56
=log3 56/log3 14 换成以3为底
=(log3 7×8)/(log3 2×7)
=(log3 7+3log3 2)/(log3 2+log3 7)
=(b+3/a)/(b+1/a)
=(ab+3)/(ab+1)=(b+3/a)/(b+1/a)=(ab+3)/(ab+1)这步是怎么来的？？分子分母同时乘以a