Answer:
C
Step-by-step explanation:
first of all, the correct factorization is
y = (x - 3)(x + 6)
because when we do the multiplication
y = x² + 6x - 3x - 18 = x² + 3x - 18
and then, the factorization tends us also directly the zero points, because y is only 0, when one of the factors is 0.
so, either x-3 or x+6 has to be 0 to make the whole expression 0.
and that is only for x=3 or x=-6
