30)log(12)(3*4)=log(12)12=1
31)log(2)(√3*2/√3)=log(2)2=1
32)log(7)(196/2²)log(7)49=2
33)log(2)(5*56/35)=log(2)8=3
34)10^lg3*10^log2=3*2=6
35)3log(ab)b*1/log(ab)b=3
36)lg(2*3)/lg(3,6*10)=lg6/lg36=log(36)6=1/2
37)2²/2^log(2)5 +2^log(2)(1/5)=4/5+1/5=5/5=1
38)log(a)a³=3
39)log(a)2²* log(a)a²/log(a)2³=2log(a)2*2/3log(a)2=4/3
40)(2log(3)a+log(a3)a):log(3)a/4=3log(3)a*4/log(3)a=12