㏒6(㏒7(
)) + 9㏒8(
)=
㏒6(㏒7(
)) + 9㏒2^3(
)=
㏒6(1/6*㏒7(7)) + 9(4/3*3)㏒2(2)=㏒6(1/6*1) + 4*1=-1 + 4= 3
2) 
3) log√3(5)*log25(6)*log6(27)=
log
(5)*log
(6)*log6(
)=
2*2*3log3(5)*log5(6)*log6(3)=12log3(5)*log5(6)*log6(3)=
12log3(5)*log5(6)*(log5(3)/log5(6))=12log3(5)*log5(3)=
12log3(5)*(1/log3(5))=12