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...
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.
The second example...
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 ...
Is this clearer now?