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# C1 - not sure how to start this watch

1. Given that 64^y = 2^3y-1, find the value of y. I don't even know where to begin.
2. Use logs I think
3. Look up "logarithms".
4. so Logy64=Log(3y-1)2
5. 64 = 8^2
8 = 2^3

therefore 2^6 = 64

2^6y = 2^3y-1

6y = 3y-1 (base the same)

rearrange to get y (I presume -1 is part of the power)
6. (Original post by Texxers)
so Logy64=Log(3y-1)2
logs is in C2, not C1
7. (Original post by Chef289)
64 = 8^2
8 = 2^3

therefore 2^6 = 64

2^6y = 2^3y-1

6y = 3y-1 (base the same)

rearrange to get y (I presume -1 is part of the power)
I wish I could find more similar problems in my C1 textbook. How did you go about doing it? I understand what you did, but I don't get why.
8. Firstly change them all to the same base Once you have that you can equal the powers
9. Laws of indices: (2^3)^y is the same as 2^3y

basically keep changing them until its the same base, and then you'll have something where both sides are equivalent and you can equal to powers
10. (Original post by Student1914)
I wish I could find more similar problems in my C1 textbook. How did you go about doing it? I understand what you did, but I don't get why.
Here's a website that tells you the basics. Law of Indices.

http://mathematics.laerd.com/maths/indices-intro.php
11. (Original post by nisha.sri)
Firstly change them all to the same base Once you have that you can equal the powers
(Original post by potassiumnitrate)
Laws of indices: (2^3)^y is the same as 2^3y

basically keep changing them until its the same base, and then you'll have something where both sides are equivalent and you can equal to powers
(Original post by Chef289)
Here's a website that tells you the basics. Law of Indices.

http://mathematics.laerd.com/maths/indices-intro.php
Thanks guys, I get it now.

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