If you notice that the first term is a perfect square, and the second term is a perfect square, and you have a negative here, we can say that it is "the difference of two squares." What we want to do ...

For example, x 2 9 would be the difference of two squares as x 2 is a squared term (x has been multiplied by itself) and 9 is a square number (3 × 3).

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