Question 350743
Since you can't take the square root of a negative number, this means that {{{13-x>=0}}}. Solve for 'x' to get {{{x<=13}}}




So the domain is {{{x<=13}}} which in interval notation is <font size="8">(</font>*[Tex \LARGE \bf{-\infty,13}]<font size="8">]</font>



The basic idea with interval notation is that you're simply listing the boundaries of the set of numbers. In this case, the smallest number is negative infinity (ie there is no smallest number) and the largest number is 13 (and we're including 13)



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Jim