高一 数学 数学对数 请详细解答,谢谢! (5 15:21:54)

log3 5-log3 15+1/2log9 27
=log3 5-log3 15+1/2(lg27/lg9)
=log3 (5÷15)+1/2(3lg3/2g3)
=log3 (1/3) +1/2*3/2
=log3 3^(-1)+1/2*3/2
=-1+3/4
=-1/4

log3 5-log3 15+1/2log9 27
=log3 5-log3 (3x5)+1/2log3 27/log3 9
=log3 5-log3 3-log3 5+1/2*3/2
=-1+3/4
=-1/4

log3 5-log3 15+1/2log9 27
=log3(5/15)+1/2(log3 27 / log3 9)
=log3(1/3)+1/2*3/2
=-1+3/4
=-1/4

log3 5-log3 15+1/2log9 27
=log3 (5/15)+(1/2)log3^2 3^3
=log3 3^(-1) + (3/4)log3 3
=-1+3/4
=-1/4

log3 5-log3 15+1/2log9 27
=log3 5-log3 (3*5)+1/2log3^2 （3^3）
=-1+1/2*(3/2)
=-1/4

log3 5-log3 15+1/2log9 27

=log3 5-log3 15+1/2(lg27/lg9)

=log3 (5÷15)+1/2(3lg3/2g3)

=log3 3^(-1)+1/2*3/2

=-1/4