Answer:
-5
Step-by-step explanation:
The power rule can be used.
f(x) = 5x^-1
f'(x) = 5(-1)x^(-1-1)
f'(x) = -5x^-2
Then ...
f'(-1) = -5(-1)^-2
f'(-1) = -5
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The attached graph shows the value of the derivative at x=-1, along with a tangent line having that slope at the point (-1, f(-1)).
