Posted by logarithms on .
how do you perform this??
log x + log(x+3) = 1

algebra 
Reiny,
One of the main rules of logs is
Log(AB) = Log A + Log B, as long as the base is the same
so log x + log(x+3) = 1
Log (x(x+3)) = 1
Log(x^2 + 3x) = 1
x^2 + 3x = 10^1
x^2 + 3x  10 = 0
(x+5)(x2) = 0
x=5 or x=2
but in log x , x must be greater than 0
so x = 2