已知f(x)＝log以a为底,X（大于零,不等于1,满足f（6）＝5,则f(4)+f(9)等于几
问题描述：
已知f(x)＝log以a为底,X（大于零,不等于1,满足f（6）＝5,
则f(4)+f(9)等于几
答
f(4)+f(9)=loga 4+loga 9=loga (4*9)=loga 36=loga (6*6)=loga 6+loga 6=2f（6）=2*5=10
答
25
答
f（6）＝5
f(4)+f(9)=loga(4)+loga(9)
=loga(36)
=2loga(6)
=2f(6)
=2*5
=10