6^6+6^6+6^6+6^6+6^6+6^6+6^6=6^a
a is?
66+66+66+66+66+66+66=6a7∗66=6alog(7∗66)=log6alog(7∗66)=alog6log(7∗66)log6=a
log10(7×66)log10(6)=7.0860331325016913