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Hello! It’s Rose I need help with this practice problem I will include another picture with the rest of the answer options (total of four answer options to the problem)

Hello! It’s Rose I need help with this practice problem I will include another picture-example-1
User IFreilicht
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1 Answer

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The given function is:


f(x)=(x^2-x-6)/(x^2+6x+8)

Vertical asymptotes occur when the denominator of the function is equal to zero.

The denominator can be factored and rewritten as:


x^2+6x+8=(x+4)(x+2)

The numerator also can be factored and rewritten as:


x^2-x-6=(x-3)(x+2)

Then the function is:


f(x)=((x-3)(x+2))/((x+4)(x+2))

Simplify (x+2)/(x+2):


f(x)=((x-3))/((x+4))

Equal the denominator to zero and find the x-value that make the function undefined:


\begin{gathered} x+4=0 \\ \therefore x=-4 \end{gathered}

There is a horizontal asymptote at x=-4.

The horizontal asymptotes occur when:

- The degree of the numerator is less than the degree of the denominator or

- The degree of the numerator is equal to the degree of the denominator.

In this case, the degree of the numerator is 2 and the degree of the denominator is 2, then they are equal. The horizontal asymptote, in this case, is at:


y=(a)/(b)

Where a is the leading coefficient in the numerator and b is the leading coefficient in the denominator.

The leading coefficient in the numerator is 1, and the leading coefficient in the denominator is 1. Then the horizontal asymptote is at y=1:


y=(1)/(1)=1

Also, the function at x=-2.1 is:


\begin{gathered} f(-2.1)=((-2.1)^2-(-2.1)-6)/((-2.1)^2+6(-2.1)+8) \\ f(-2.1)=(4.41+2.1-6)/(4.41-12.6+8) \\ f(-2.1)=(0.51)/(-0.19) \\ f(-2.1)=-2.7 \end{gathered}

Answer: As can be seen, the function that matches with the asymptotes and f(-2.1)=-2.7 is the first graph.

User The Bic Pen
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