There's an easier way. Multiply your and values together. You need to find two numbers that multiply to become and add to become .

To use the examples on that page...

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Multiplying our and values gives . So we need two numbers that multiply to give and add to be . They are and .

So we break up the middle value into and then factorise by grouping.

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The second example...

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Multiply the and values, we get . So we need two numbers that multiply to give and add to . They are and .

Break up the middle term into ...

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Is this clearer now?