what is the answer for 16^x-3=4^x-3?

In YahooAnswer, we normally use the caret ^ to indicate raising to a power;

For example, x^3 means x cubed = x x x (x multiplied by itself for a total of three times).

4^3 = 4*4*4 = 64

If we need to use a sign for multiplication, we normally use the asterisk *

We also use brackets to show the order of the operations.

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If your problem really is:

(16^x) -3 = (4^x) - 3
Then it can be solved only if
16^x = 4^x

That will be true only if x=0

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If your problem is
16^(x-3) = 4^(x-3)

16 raised to the power of (x-3) is equal to 4 raised to the power (x-3), then it will only be true when (x-3)=0
(Because any number "raised to the power 0" is equal to 1)

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If your problem is:

16x - 3 = 4x - 3
Then x must be 0 again (but for a different reason)

For heaven's sake people, use parenthesis when righting down a math equation! I could give you 4 answers based alone on the mal-written formula you just gave us. Seriously....

16^(x - 3) = 4^(x - 3)
(4^2)^(x - 3) = 4^(x - 3)
4^[2(x - 3)] = 4^(x - 3)
2(x - 3) = x - 3
2*x - 2*3 = x - 3
2x - 6 = x - 3
2x - x = 6 - 3
x = 3

6^(x-3) = 4^(x-3)

4^2(x-3) = 4^(x-3)

2(x-3) = (x-3)

>> No solution.

X=3

16^0=1
4^0=1

no solution