Respuesta :

hello : 
f(x) = x²+10x+12
f(x) = (x²+2(5)x+5²)-5² +12
f(x) = (x+5)²-13 
the x-intercepts solutions f(x) = 0
(x+5)² -13 =0
(x+5)² =(
√13)²
x+5 =
√13 or x+5 = -√13
x= √13 -5 or x= -√13 -5