Determine the tangent line of $f(x)=(x-1)(x^2-4)$ at $x=-1$.

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Lesson Parent: 
The Formula of the Tangent Line
Problem: 

Determine the tangent line of $f(x)=(x-1)(x^2-4)$ at $x=-1$.

Answer: 

$y=x+7$

SAMPLE SOLUTION

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Solution: 

We know that the general formula for the tangent line at a point $x_o$ for $f(x)$ is

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In this problem <Sign in to see all the formulas>. So <Sign in to see all the formulas>. We have already found that

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So <Sign in to see all the formulas>.

Therefore, the formula for the tangent line at $x=-1$ is

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