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# C2 Logs question watch

1. How would I answer 3 x 2^x = 7^x-2. I keep trying and getting -29.145, which is obviously wrong. Thanks in advance
2. (Original post by doglover123)
How would I answer 3 x 2^x = 7^x-2. I keep trying and getting -29.145, which is obviously wrong. Thanks in advance
I'm sorry the photo is sideways, i have no idea how to rotate it
3. Bring the x terms to one side and factorise.
4. (Original post by doglover123)
How would I answer 3 x 2^x = 7^x-2. I keep trying and getting -29.145, which is obviously wrong. Thanks in advance
What I done was divide both sides by

So

Then take logs of both sides and use the rule. Then find a way of factorising

Your mistake lies in the first line of your working out. Taking log to does not equal

It is and again from here you can use the rule to work it out also
5. (Original post by edothero)
What I done was divide both sides by

So

Then take logs of both sides and use the rule. Then find a way of factorising

Your mistake lies in the first line of your working out. Taking log to does not equal

It is and again from here you can use the rule to work it out also
THANK YOU SO MUCH! Everything became a lot clearer once I divided by 2^x
6. (Original post by doglover123)
THANK YOU SO MUCH! Everything became a lot clearer once I divided by 2^x
No problem I'm glad I helped. Also I hope you took note about your mistake and why it was wrong! Always good to learn from mistakes

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