What does x equal if #log(7x)=2#?

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Answer 1 · 2018-05-17T18:10:54

#x=100/7#

#log7x=2#

But #2=log100# (because #10^2=100#) hence

#log7x=log100#

By inyectivity of log function we can say that #7x=100#

#x=100/7#

This a valid solution because #log(7·100/7)=log100=2#

Answer 2 · 2018-05-17T18:50:36

#x=100/7#

We have #log_10(7x)=2#

which can be rewritten as

#10^2=7x#

#=>100=7x#

Dividing both sides by #7#, we get

#x=100/7#

Hope this helps!