7log8^9=a log3^5=b 求lg2 lg3 lg5

7 *(2/3)log2(3)=a
log2(3)=3a/14
log3(2)=14/(3a)
log3(5)=b
lg2=log3(2)/log3(10)=log3(2)/[log3(2)+log3(5)]=[14/(3a)]/[14/(3a)+b]=14/(14+3ab)
lg3=1/log3(10)=1/[log3(2)+log3(5)]=1/[14/(3a)+b]=3a/(14+3ab)
lg5=1-lg2=1- 14/(14+3ab)=3ab/(14+3ab)