How do you solve #ln(9r+1)=ln(r^2+9)#?

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Answer 1 · 2016-09-03T19:14:38

The Soln. is #r=8,1#.

Since, #ln# function is #1-1#,

#ln(9r+1)=ln(r^2+9)#

# rArr 9r+1=r^2+9, or, r^2-9r+8=0#

# rArr (r-8)(r-1)=0#

# rArr r=8, r=1#.

Both these roots satisfy the given eqn. Hence,

The Soln. is #r=8,1#.