WEBVTT

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Here is the problem: negative 4x minus 9 equals 20.

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A linear equation in x: isolate x using inverse operations.

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Start with the equation.

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Add 9 to both sides.

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Divide both sides by negative 4.

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So the answer is x equals negative 29 over 4 approximately negative 7.25.

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Doing the same operation to both sides keeps the equation balanced. Undoing addition, then multiplication, leaves x alone.

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x equals negative 7.25: left side equals 20, right side equals 20, which checks out.