WEBVTT

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Here is the problem: negative 2x minus 9 less than negative 9.

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Solve the inequality and give the answer in interval notation.

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Move everything to one side and isolate the variable. Collect terms: negative 2x less than 0. Dividing by a negative coefficient reverses the inequality sign.

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Test one point in each interval (sign chart). (-∞, 0): test x equals negative 1 → sign plus → excluded; (0, ∞): test x equals 1 → sign minus → included.

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Decide the endpoints. 0: excluded.

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Write the solution set.

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So the answer is (0, ∞).

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The inequality holds exactly for x in (0, ∞). Points where the expression is undefined are never included, and endpoints are included only for less than or equal to or greater than or equal to where the expression equals zero.

9
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x equals negative 1: does not satisfy the inequality.

10
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x equals 1: satisfies the inequality.