1. log(3; 27)=3
3^x=27
x=27
2. log(4; 1)=0
4^x=1
x=0
3. log(1/2; 4)=-2
(1/2)^x=4
x=-2
4. 6log(6; 13)=6*ln13/ln6=(6*ln13)/(ln2+ln3)
