Question 861687
{{{9log(b,x)+7log(b,z)=log(b,x^9)+log(b,z^7)=log(b,x^9z^7)}}}
 
Logarithms are really exponents,
and as long as the base is the same,
it is easy to add and subtract them.
If you add exponents, you get the the product of the powers,
as in {{{z^(3+4)=(z^3)(z^4)}}} ,
so if you add logarithms you get the logarithm of the product.