How do you solve ln(x^2+12)=lnx+ln8ln(x2+12)=lnx+ln8?

1 Answer
Oct 17, 2016

x=2 x=2 and x=6x=6

Explanation:

ln(x^2+12)=lnx+ln8ln(x2+12)=lnx+ln8
We can rewrite this as ln(x^2+12)=ln8xln(x2+12)=ln8x
Removing the ln on both sides,give
x^2+12=8xx2+12=8x
Rearranging
x^2-8x+12=0x28x+12=0
(x-6)(x-2)=0(x6)(x2)=0
so x=6 or x=2
We have to check the conditions for ln
x^2+12>0x2+12>0and 8x>08x>0
So the solution is ok