How do you solve ln(x+1)-ln(x-2)=lnx^2ln(x+1)ln(x2)=lnx2?

1 Answer
Jan 16, 2016

From laws of logs we get

ln[(x+1)/(x-2)]=lnx^2ln[x+1x2]=lnx2

therefore (x+1)/(x-2)=x^2

therefore x^3-2x^2-x-1=0

This is now a 3rd degree polynomial so you will have to try using the factor and remainder theorem to find the roots, otherwise you will have to use a numerical technique such as Newton's method of root-finding.

I leave the details as an exercise. Please ask if you are still stuck.