# Solving exponentials using logs exam question help

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#1
Attachment 774266 can someone explain how to work out part c please?
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2 years ago
#2
(Original post by Jsimons56)
Attachment 774266 can someone explain how to work out part c please?
What have you tried so far?
0
2 years ago
#3
(Original post by Jsimons56)
can someone explain how to work out part c please?
Equate the two equations, standard procedure.

Apply the logs,

Quick note that so we must simplify the log,

Use these two rules,

Therefore,

Now I hope you know how to make the subject given that I've written a note underneath the log(5) and log(9).

Now, you're not finished here.

Use this rule below last after using the two rules above first to get the required answer.

(Alternatively, you can also have )

Since this is maths, there's probably a faster method than mine but this was how I worked it out.
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