Respuesta :

you set everything to 0, so when u do that all u need to do is FOIL to find the x-intercept, meaning whatever x is equal to.
We are given with the function y = x² - x - 12 and is asked to find the x-intercept applying the zero property. The x-intercept is obtained when y = 0. Hence, 

 y = x² - x - 12 = 0
 (x-4) (x+3) = 0
 Using zero property, we equate the two factors to zero

(x-4) = 0
x = 4
 (x+3) = 0
x=3

the zero property help find the solution set or y-intercept of the function