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What does x equal?

2007-01-22 08:33:07 · 3 answers · asked by girl_pink 1 in Education & Reference Homework Help

Thats:

Log base 2 (3x - 10) - log base 2 (x - 3) = 2?

2007-01-22 08:33:26 · update #1

3 answers

ok. when you subtract logs with the same base, it's like taking the log of the quotient of what you have in the perentheses.
(log base 2 (y) - log base 2 (x) = log base 2 (y/x) ) When you add logs it's like taking the log of the product.

So,

log base 2 (3x-10) - log base 2 (x-3) = 2

can be rewritten:

log base 2 ((3x - 10) / (x - 3)) = 2

When you have a log base something = to a number, you can raise the number to the base. For example log base 2 (x) = 4. Then 2 ^ 4 = x.

So, in this case:

2 ^ 2 = (3x -10) / (x - 3)

Now multiply both sides by (x - 3)

4x - 12 = 3x - 10

Subtract 3x from each side:

x - 12 = -10

Add 12 to each side:

x= 2

2007-01-22 08:42:49 · answer #1 · answered by Ace 4 · 0 0

5

2007-01-22 16:36:42 · answer #2 · answered by smilie:) 2 · 0 0

x=2. when you have something like log base x (Y) - log base x (Z), it is equal to log base x(Y/Z).

2007-01-22 16:44:25 · answer #3 · answered by Anonymous · 0 0

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