How do we solve quadratic equations by factoring ?

Zero Product Property states that when the product of 2 factors equal zero , than at least one of the 2 factors must equal zero.  EX: if 4 (  X-7 )=0 than 4 or ( X-7) must be zero . 

Step 1 : Factor if not already 

Step 2 :  Take each part of the factored equation and create an equation that equals to zero 

Step 3 : Solve ! 

Step 4 : Check by substitution if you are not sure .

EX : (X-1)(X-4)  ------ >    X-1 =0  and X-4=0 
                              +1  +1      +4 +4
                                              
                           X =1          X = 4 

Short Cut : When you reach the factored equation just switch the signs . You can do it mentally .

EX : ( X-6 ) ( X+2)  ------ > X=6    X=-2