WEBVTT

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Here is the problem: 8x plus 12 equals negative 4x minus 9.

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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 4x to both sides.

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Subtract 12 from both sides.

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Divide both sides by 12.

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So the answer is x equals negative 7 over 4 approximately negative 1.75.

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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 1.75: left side equals negative 2, right side equals negative 2, which checks out.