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Find the domain of the function defined in the picture .state answer in interval form.

Find the domain of the function defined in the picture .state answer in interval form-example-1
User Andrew McGivery
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1 Answer

26 votes
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We will determine the domain of the function as follows:


(x+7)/(x^2-11x+24)=(x+7)/((x-3)(x-8))

So, the domain is the following:


D=\mleft(-\infty,3\mright)\wedge(3,8)\wedge(8,\infty)

**Explanation***

In order to determine the domain of the function, we factor the denominator and evaluate at which points the denominator will become zero. [When this happens the function is not defined and thus those values do not belong in the domain].

When we factor the denominator, we obtain:


x^2-11x+24=(x-3)(x-8)

So, we equal the factor to zero and find which points do not belong in the domain:


(x-3)(x-8)=0\Rightarrow\begin{cases}x=3 \\ x=8\end{cases}

So, the equation "makes sense" in all of the real numbers, except when x = 3 and x = 8.

User Vahagn
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