**6throute (x-7)**

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log

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log

_{11}(13-x)What is the domain of the function in interval notation.

I know to set x-7 > 0, so that gets me x>7 , and I know I have to set 13-x > 0, which gets me x < 13. But the notation that is correct is [7,12)U(12,13). Where do you get the 12 from?