WEBVTT

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Here is the problem: 3a plus 4 equals 19.

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

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Start with the equation.

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Subtract 4 from both sides.

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Divide both sides by 3.

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So the answer is a equals 5.

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

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a equals 5: left side equals 19, right side equals 19, which checks out.