remember some simple log rules
[tex]log(a)+log(b)=log(ab)[/tex]
and
[tex]log(a)-log(b)=log(\frac{a}{b})[/tex]
work from left to right
[tex]log(12)-log(4)+log(5)=[/tex]
[tex]log(\frac{12}{4})+log(5)=[/tex]
[tex]log(3)+log(5)=[/tex]
[tex]log(3*5)=[/tex]
[tex]log(15)[/tex]