Question

Question

Answer 1

Answer:  $(-\infty ,-0.12]$

Curved parenthesis for negative infinity. Square bracket for the -0.12

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Explanation:

The inequality $x \le -0.12$ is the same as $-\infty < x \le -0.12$

This says that x is larger than negative infinity, but smaller than or equal to -0.12

Put another way: x is between negative infinity and -0.12, x could also equal -0.12

To write this in interval notation, we would say $(-\infty ,-0.12]$

We always use a curved parenthesis for either infinity. The square bracket indicates "include this endpoint as part of the interval".