WEBVTT

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Here is the problem: (x plus y)(x minus y).

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Expand (x plus y)(x minus y) and collect like terms.

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Read the expression.

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Distribute (multiply out every product). Each term in one factor multiplies each term in the other: a(b plus c) equals ab plus ac.

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Result after multiplying out.

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Combine like terms. xy: negative 1 plus 1 equals 0. Like terms have identical variables and exponents, so only their coefficients are added.

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Write the result in standard form. Terms are ordered by descending total degree.

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So the answer is x squared minus y squared.

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After expanding and combining like terms the expression is x squared minus y squared, a polynomial of degree 2 with 2 terms.

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Spot check at x equals 0.73, y equals 1.14: original negative 0.7667, simplified negative 0.7667, which checks out.