第1个回答 2008-11-03
首先要用到的公式
1)loga x+loga y=loga (x*y)
2)loga x-loga y=loga (x/y)
3)logx y=loga y /loga x
log18 18 +log18 2
=log18 (18*2)
=log18 (18*18/9)
=log18 (18^2/9)
=log18 18^2-log18 9
=(2-a)
log36 45
=log18 45/log18 36
=log18 (5*9)/log18 (18*2)
=(log18 5+log18 9)/(log18 18+log18 2)
=(a+b)/(2-a)