The given graph of the DERIVATIVE $f'$ of a function $f$ is shown. Assuming the graph continue in the same way as $x$ goes to infinity and negative infinity, answer the following questions.

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1. On what intervals is $f$ increasing?
Answer (in interval notation):

2. On what intervals is $f$ decreasing?
Answer (in interval notation):

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Note: You can click on the graph to enlarge the image.

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Hint: