Question

I forgot logarithms :/
log_5(8r-7)=log_5(r^2+5)

Answer 1

if:\[\log_bA=\log_bB\implies A=B\]

Answer 2

So all I need to do is set them equal to eachother? Sorry, I kinda forgot all this, and studying again.

Answer 3

yes, so assuming your question is:\[\log_5(8r-7)=\log_5(r^2+5)\]then you would have:\[8r-7=r^2+5\]solve this for r.

Answer 4

Okay, but if i were to have something like:
log_9(x+4)+log_9(x-4)=1

Answer 5

then you would use the rule:\[\log_bA+\log_bB=\log_b(A*B)\]

Answer 6

Ohhhh, okay, these rules are making its simple, are there any other important so I can study them? If you dont mind posting..

Answer 7

*Important rules

Answer 8

See this: http://www.purplemath.com/modules/logrules.htm

Answer 9

Perfect, thanks soo much!!

Answer 10

yw :)