factoring quadratic equations

 

   how do we factor quadratic equations? for example how do we factor x2-9?     

 

   x² – 9 isn't a typica; example, but is a special case: "the difference of squares".     

   You recognize that x² is a square (duh LoL), also that 9 is a square, namely 3².     

   When you have the difference of squares, x² – y², you factor it as (x + y)(x – y).     

   The specific example you cited, x² – 9, this would be factored as (x + 3)(x – 3).     

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