log2(25)*log3(4)*log5(9) =lg25/lg2*lg4/lg3*lg9/lg5 (换底公式) =lg5^2/lg2*lg2^2/lg3*lg3^2/lg5 =2lg5/lg2*2lg2/lg3*2lg3/lg5 =2(lg5/lg2)*2(lg2/lg3)*2(lg3/lg5) =8*1 =8采纳哦